# Hadoop Change Log

## Release 0.20.1 - 2009-09-01

- INCOMPATIBLE CHANGES (2)
  1. HADOOP-5726. Remove pre-emption from capacity scheduler code base.
     (Rahul Kumar Singh via yhemanth)
  2. HADOOP-5881. Simplify memory monitoring and scheduling related configuration.
     (Vinod Kumar Vavilapalli via yhemanth)
- NEW FEATURES (2)
  1. HADOOP-6080. Introduce -skipTrash option to rm and rmr.
     (Jakob Homan via shv)
  2. HADOOP-3315. Add a new, binary file foramt, TFile.
     (Hong Tang via cdouglas)
- IMPROVEMENTS (7)
  1. HADOOP-5711. Change Namenode file close log to info.
     (szetszwo)
  2. HADOOP-5736. Update the capacity scheduler documentation for features like memory based scheduling, job initialization and removal of pre-emption.
     (Sreekanth Ramakrishnan via yhemanth)
  3. HADOOP-4674. Fix fs help messages for -test, -text, -tail, -stat and -touchz options.
     (Ravi Phulari via szetszwo)
  4. HADOOP-4372. Improves the way history filenames are obtained and manipulated.
     (Amar Kamat via ddas)
  5. HADOOP-5897. Add name-node metrics to capture java heap usage.
     (Suresh Srinivas via shv)
  6. HDFS-438. Improve help message for space quota command.
     (Raghu Angadi)
  7. MAPREDUCE-767. Remove the dependence on the CLI 2.0 snapshot.
     (Amar Kamat via ddas)
- OPTIMIZATIONS (none)
- BUG FIXES (65)
  1. HADOOP-5691. Makes org.apache.hadoop.mapreduce.Reducer concrete class instead of abstract.
     (Amareshwari Sriramadasu via sharad)
  2. HADOOP-5646. Fixes a problem in TestQueueCapacities.
     (Vinod Kumar Vavilapalli via ddas)
  3. HADOOP-5655. TestMRServerPorts fails on java.net.BindException.
     (Devaraj Das via hairong)
  4. HADOOP-5654. TestReplicationPolicy.<init> fails on java.net.BindException.
     (hairong)
  5. HADOOP-5688. Fix HftpFileSystem checksum path construction. (Tsz Wo (Nicholas) Sze via cdouglas)
  6. HADOOP-5213. Fix Null pointer exception caused when bzip2compression was used and user closed a output stream without writing any data.
     (Zheng Shao via dhruba)
  7. HADOOP-5718. Remove the check for the default queue in capacity scheduler.
     (Sreekanth Ramakrishnan via yhemanth)
  8. HADOOP-5719. Remove jobs that failed initialization from the waiting queue in the capacity scheduler.
     (Sreekanth Ramakrishnan via yhemanth)
  9. HADOOP-4744. Attaching another fix to the jetty port issue. The TaskTracker kills itself if it ever discovers that the port to which jetty is actually bound is invalid (-1).
     (ddas)
  10. HADOOP-5349. Fixes a problem in LocalDirAllocator to check for the return path value that is returned for the case where the file we want to write is of an unknown size.
      (Vinod Kumar Vavilapalli via ddas)
  11. HADOOP-5636. Prevents a job from going to RUNNING state after it has been KILLED (this used to happen when the SetupTask would come back with a success after the job has been killed).
      (Amar Kamat via ddas)
  12. HADOOP-5641. Fix a NullPointerException in capacity scheduler's memory based scheduling code when jobs get retired.
      (yhemanth)
  13. HADOOP-5828. Use absolute path for mapred.local.dir of JobTracker in MiniMRCluster.
      (yhemanth)
  14. HADOOP-4981. Fix capacity scheduler to schedule speculative tasks correctly in the presence of High RAM jobs.
      (Sreekanth Ramakrishnan via yhemanth)
  15. HADOOP-5210. Solves a problem in the progress report of the reduce task.
      (Ravi Gummadi via ddas)
  16. HADOOP-5850. Fixes a problem to do with not being able to jobs with 0 maps/reduces.
      (Vinod K V via ddas)
  17. HADOOP-5728. Fixed FSEditLog.printStatistics IndexOutOfBoundsException.
      (Wang Xu via johan)
  18. HADOOP-4626. Correct the API links in hdfs forrest doc so that they point to the same version of hadoop.
      (szetszwo)
  19. HADOOP-5883. Fixed tasktracker memory monitoring to account for momentary spurts in memory usage due to java's fork() model.
      (yhemanth)
  20. HADOOP-5539. Fixes a problem to do with not preserving intermediate output compression for merged data.
      (Jothi Padmanabhan and Billy Pearson via ddas)
  21. HADOOP-5932. Fixes a problem in capacity scheduler in computing available memory on a tasktracker.
      (Vinod Kumar Vavilapalli via yhemanth)
  22. HADOOP-5648. Fixes a build issue in not being able to generate gridmix.jar in hadoop binary tarball.
      (Giridharan Kesavan via gkesavan)
  23. HADOOP-5908. Fixes a problem to do with ArithmeticException in the JobTracker when there are jobs with 0 maps.
      (Amar Kamat via ddas)
  24. HADOOP-5924. Fixes a corner case problem to do with job recovery with empty history files. Also, after a JT restart, sends KillTaskAction to tasks that report back but the corresponding job hasn't been initialized yet.
      (Amar Kamat via ddas)
  25. HADOOP-5882. Fixes a reducer progress update problem for new mapreduce api.
      (Amareshwari Sriramadasu via sharad)
  26. HADOOP-5746. Fixes a corner case problem in Streaming, where if an exception happens in MROutputThread after the last call to the map/reduce method, the exception goes undetected.
      (Amar Kamat via ddas)
  27. HADOOP-5884. Fixes accounting in capacity scheduler so that high RAM jobs take more slots.
      (Vinod Kumar Vavilapalli via yhemanth)
  28. HADOOP-5937. Correct a safemode message in FSNamesystem.
      (Ravi Phulari via szetszwo)
  29. HADOOP-5869. Fix bug in assignment of setup / cleanup task that was causing TestQueueCapacities to fail.
      (Sreekanth Ramakrishnan via yhemanth)
  30. HADOOP-5921. Fixes a problem in the JobTracker where it sometimes never used to come up due to a system file creation on JobTracker's system-dir failing. This problem would sometimes show up only when the FS for the system-dir (usually HDFS) is started at nearly the same time as the JobTracker.
      (Amar Kamat via ddas)
  31. HADOOP-5920. Fixes a testcase failure for TestJobHistory.
      (Amar Kamat via ddas)
  32. HDFS-26. Better error message to users when commands fail because of lack of quota. Allow quota to be set even if the limit is lower than current consumption.
      (Boris Shkolnik via rangadi)
  33. MAPREDUCE-2. Fixes a bug in KeyFieldBasedPartitioner in handling empty keys.
      (Amar Kamat via sharad)
  34. MAPREDUCE-130. Delete the jobconf copy from the log directory of the JobTracker when the job is retired.
      (Amar Kamat via sharad)
  35. MAPREDUCE-657. Fix hardcoded filesystem problem in CompletedJobStatusStore.
      (Amar Kamat via sharad)
  36. MAPREDUCE-179. Update progress in new RecordReaders.
      (cdouglas)
  37. MAPREDUCE-124. Fix a bug in failure handling of abort task of OutputCommiter.
      (Amareshwari Sriramadasu via sharad)
  38. HADOOP-6139. Fix the FsShell help messages for rm and rmr.
      (Jakob Homan via szetszwo)
  39. HADOOP-6141. Fix a few bugs in 0.20 test-patch.sh.
      (Hong Tang via szetszwo)
  40. HADOOP-6145. Fix FsShell rm/rmr error messages when there is a FNFE.
      (Jakob Homan via szetszwo)
  41. MAPREDUCE-565. Fix partitioner to work with new API.
      (Owen O'Malley via cdouglas)
  42. MAPREDUCE-465. Fix a bug in MultithreadedMapRunner.
      (Amareshwari Sriramadasu via sharad)
  43. MAPREDUCE-18. Puts some checks to detect cases where jetty serves up incorrect output during shuffle.
      (Ravi Gummadi via ddas)
  44. MAPREDUCE-735. Fixes a problem in the KeyFieldHelper to do with the end index for some inputs
      (Amar Kamat via ddas)
  45. HADOOP-6150. Users should be able to instantiate comparator using TFile API.
      (Hong Tang via rangadi)
  46. MAPREDUCE-383. Fix a bug in Pipes combiner due to bytes count not getting reset after the spill.
      (Christian Kunz via sharad)
  47. MAPREDUCE-40. Keep memory management backwards compatible for job configuration parameters and limits.
      (Rahul Kumar Singh via yhemanth)
  48. MAPREDUCE-796. Fixes a ClassCastException in an exception log in MultiThreadedMapRunner.
      (Amar Kamat via ddas)
  49. MAPREDUCE-838. Fixes a problem in the way commit of task outputs happens. The bug was that even if commit failed, the task would be declared as successful.
      (Amareshwari Sriramadasu via ddas)
  50. MAPREDUCE-805. Fixes some deadlocks in the JobTracker due to the fact the JobTracker lock hierarchy wasn't maintained in some JobInProgress method calls.
      (Amar Kamat via ddas)
  51. HDFS-167. Fix a bug in DFSClient that caused infinite retries on write.
      (Bill Zeller via szetszwo)
  52. HDFS-527. Remove unnecessary DFSClient constructors.
      (szetszwo)
  53. MAPREDUCE-832. Reduce number of warning messages printed when deprecated memory variables are used.
      (Rahul Kumar Singh via yhemanth)
  54. MAPREDUCE-745. Fixes a testcase problem to do with generation of JobTracker IDs.
      (Amar Kamat via ddas)
  55. MAPREDUCE-834. Enables memory management on tasktrackers when old memory management parameters are used in configuration.
      (Sreekanth Ramakrishnan via yhemanth)
  56. MAPREDUCE-818. Fixes Counters#getGroup API.
      (Amareshwari Sriramadasu via sharad)
  57. MAPREDUCE-807. Handles the AccessControlException during the deletion of mapred.system.dir in the JobTracker. The JobTracker will bail out if it encounters such an exception.
      (Amar Kamat via ddas)
  58. HADOOP-6213. Remove commons dependency on commons-cli2.
      (Amar Kamat via sharad)
  59. MAPREDUCE-430. Fix a bug related to task getting stuck in case of OOM error.
      (Amar Kamat via ddas)
  60. HADOOP-6215. fix GenericOptionParser to deal with -D with '=' in the value.
      (Amar Kamat via sharad)
  61. MAPREDUCE-421. Fix Pipes to use returned system exit code.
      (Christian Kunz via omalley)
  62. HDFS-525. The SimpleDateFormat object in ListPathsServlet is not thread safe.
      (Suresh Srinivas and cdouglas)
  63. MAPREDUCE-911. Fix a bug in TestTaskFail related to speculative execution.
      (Amareshwari Sriramadasu via sharad)
  64. MAPREDUCE-687. Fix an assertion in TestMiniMRMapRedDebugScript.
      (Amareshwari Sriramadasu via sharad)
  65. MAPREDUCE-924. Fixes the TestPipes testcase to use Tool.
      (Amareshwari Sriramadasu via sharad)

## Release 0.20.0 - 2009-04-15

- INCOMPATIBLE CHANGES (20)
  1. HADOOP-4210. Fix findbugs warnings for equals implementations of mapred ID classes. Removed public, static ID::read and ID::forName; made ID an abstract class.
     (Suresh Srinivas via cdouglas)
  2. HADOOP-4253. Fix various warnings generated by findbugs. Following deprecated methods in RawLocalFileSystem are removed: public String getName() public void lock(Path p, boolean shared) public void release(Path p)
     (Suresh Srinivas via johan)
  3. HADOOP-4618. Move http server from FSNamesystem into NameNode. FSNamesystem.getNameNodeInfoPort() is removed. FSNamesystem.getDFSNameNodeMachine() and FSNamesystem.getDFSNameNodePort() replaced by FSNamesystem.getDFSNameNodeAddress(). NameNode(bindAddress, conf) is removed.
     (shv)
  4. HADOOP-4567. GetFileBlockLocations returns the NetworkTopology information of the machines where the blocks reside.
     (dhruba)
  5. HADOOP-4435. The JobTracker WebUI displays the amount of heap memory in use.
     (dhruba)
  6. HADOOP-4628. Move Hive into a standalone subproject.
     (omalley)
  7. HADOOP-4188. Removes task's dependency on concrete filesystems.
     (Sharad Agarwal via ddas)
  8. HADOOP-1650. Upgrade to Jetty 6.
     (cdouglas)
  9. HADOOP-3986. Remove static Configuration from JobClient. (Amareshwari Sriramadasu via cdouglas) JobClient::setCommandLineConfig is removed JobClient::getCommandLineConfig is removed JobShell, TestJobShell classes are removed
  10. HADOOP-4422. S3 file systems should not create bucket.
      (David Phillips via tomwhite)
  11. HADOOP-4035. Support memory based scheduling in capacity scheduler.
      (Vinod Kumar Vavilapalli via yhemanth)
  12. HADOOP-3497. Fix bug in overly restrictive file globbing with a PathFilter.
      (tomwhite)
  13. HADOOP-4445. Replace running task counts with running task percentage in capacity scheduler UI.
      (Sreekanth Ramakrishnan via yhemanth)
  14. HADOOP-4631. Splits the configuration into three parts - one for core, one for mapred and the last one for HDFS.
      (Sharad Agarwal via cdouglas)
  15. HADOOP-3344. Fix libhdfs build to use autoconf and build the same architecture (32 vs 64 bit) of the JVM running Ant. The libraries for pipes, utils, and libhdfs are now all in c++/<os_osarch_jvmdatamodel>/lib.
      (Giridharan Kesavan via nigel)
  16. HADOOP-4874. Remove LZO codec because of licensing issues.
      (omalley)
  17. HADOOP-4970. The full path name of a file is preserved inside Trash.
      (Prasad Chakka via dhruba)
  18. HADOOP-4103. NameNode keeps a count of missing blocks. It warns on WebUI if there are such blocks. '-report' and '-metaSave' have extra info to track such blocks.
      (Raghu Angadi)
  19. HADOOP-4783. Change permissions on history files on the jobtracker to be only group readable instead of world readable.
      (Amareshwari Sriramadasu via yhemanth)
  20. HADOOP-5531. Removed Chukwa from Hadoop 0.20.0.
      (nigel)
- NEW FEATURES (10)
  1. HADOOP-4575. Add a proxy service for relaying HsftpFileSystem requests. Includes client authentication via user certificates and config-based access control.
     (Kan Zhang via cdouglas)
  2. HADOOP-4661. Add DistCh, a new tool for distributed ch{mod,own,grp}.
     (szetszwo)
  3. HADOOP-4709. Add several new features and bug fixes to Chukwa. Added Hadoop Infrastructure Care Center (UI for visualize data collected by Chukwa) Added FileAdaptor for streaming small file in one chunk Added compression to archive and demux output Added unit tests and validation for agent, collector, and demux map reduce job Added database loader for loading demux output (sequence file) to jdbc connected database Added algorithm to distribute collector load more evenly
     (Jerome Boulon, Eric Yang, Andy Konwinski, Ariel Rabkin via cdouglas)
  4. HADOOP-4179. Add Vaidya tool to analyze map/reduce job logs for performanc problems.
     (Suhas Gogate via omalley)
  5. HADOOP-4029. Add NameNode storage information to the dfshealth page and move DataNode information to a separated page.
     (Boris Shkolnik via szetszwo)
  6. HADOOP-4348. Add service-level authorization for Hadoop.
     (acmurthy)
  7. HADOOP-4826. Introduce admin command saveNamespace.
     (shv)
  8. HADOOP-3063 BloomMapFile - fail-fast version of MapFile for sparsely populated key space
     (Andrzej Bialecki via stack)
  9. HADOOP-1230. Add new map/reduce API and deprecate the old one. Generally, the old code should work without problem. The new api is in org.apache.hadoop.mapreduce and the old classes in org.apache.hadoop.mapred are deprecated. Differences in the new API: 1. All of the methods take Context objects that allow us to add new methods without breaking compatability. 2. Mapper and Reducer now have a "run" method that is called once and contains the control loop for the task, which lets applications replace it. 3. Mapper and Reducer by default are Identity Mapper and Reducer. 4. The FileOutputFormats use part-r-00000 for the output of reduce 0 and part-m-00000 for the output of map 0. 5. The reduce grouping comparator now uses the raw compare instead of object compare. 6. The number of maps in FileInputFormat is controlled by min and max split size rather than min size and the desired number of maps.
     (omalley)
  10. HADOOP-3305. Use Ivy to manage dependencies.
      (Giridharan Kesavan and Steve Loughran via cutting)
- IMPROVEMENTS (73)
  1. HADOOP-4565. Added CombineFileInputFormat to use data locality information to create splits.
     (dhruba via zshao)
  2. HADOOP-4749. Added a new counter REDUCE_INPUT_BYTES.
     (Yongqiang He via zshao)
  3. HADOOP-4234. Fix KFS "glue" layer to allow applications to interface with multiple KFS metaservers.
     (Sriram Rao via lohit)
  4. HADOOP-4245. Update to latest version of KFS "glue" library jar.
     (Sriram Rao via lohit)
  5. HADOOP-4244. Change test-patch.sh to check Eclipse classpath no matter it is run by Hudson or not.
     (szetszwo)
  6. HADOOP-3180. Add name of missing class to WritableName.getClass IOException.
     (Pete Wyckoff via omalley)
  7. HADOOP-4178. Make the capacity scheduler's default values configurable.
     (Sreekanth Ramakrishnan via omalley)
  8. HADOOP-4262. Generate better error message when client exception has null message.
     (stevel via omalley)
  9. HADOOP-4226. Refactor and document LineReader to make it more readily understandable.
     (Yuri Pradkin via cdouglas)
  10. HADOOP-4238. When listing jobs, if scheduling information isn't available print NA instead of empty output.
      (Sreekanth Ramakrishnan via johan)
  11. HADOOP-4284. Support filters that apply to all requests, or global filters, to HttpServer.
      (Kan Zhang via cdouglas)
  12. HADOOP-4276. Improve the hashing functions and deserialization of the mapred ID classes.
      (omalley)
  13. HADOOP-4485. Add a compile-native ant task, as a shorthand.
      (enis)
  14. HADOOP-4454. Allow # comments in slaves file.
      (Rama Ramasamy via omalley)
  15. HADOOP-3461. Remove hdfs.StringBytesWritable.
      (szetszwo)
  16. HADOOP-4437. Use Halton sequence instead of java.util.Random in PiEstimator.
      (szetszwo)
  17. HADOOP-4572. Change INode and its sub-classes to package private.
      (szetszwo)
  18. HADOOP-4187. Does a runtime lookup for JobConf/JobConfigurable, and if found, invokes the appropriate configure method.
      (Sharad Agarwal via ddas)
  19. HADOOP-4453. Improve ssl configuration and handling in HsftpFileSystem, particularly when used with DistCp.
      (Kan Zhang via cdouglas)
  20. HADOOP-4583. Several code optimizations in HDFS.
      (Suresh Srinivas via szetszwo)
  21. HADOOP-3923. Remove org.apache.hadoop.mapred.StatusHttpServer.
      (szetszwo)
  22. HADOOP-4622. Explicitly specify interpretor for non-native pipes binaries.
      (Fredrik Hedberg via johan)
  23. HADOOP-4505. Add a unit test to test faulty setup task and cleanup task killing the job.
      (Amareshwari Sriramadasu via johan)
  24. HADOOP-4608. Don't print a stack trace when the example driver gets an unknown program to run.
      (Edward Yoon via omalley)
  25. HADOOP-4645. Package HdfsProxy contrib project without the extra level of directories.
      (Kan Zhang via omalley)
  26. HADOOP-4126. Allow access to HDFS web UI on EC2
      (tomwhite via omalley)
  27. HADOOP-4612. Removes RunJar's dependency on JobClient.
      (Sharad Agarwal via ddas)
  28. HADOOP-4185. Adds setVerifyChecksum() method to FileSystem.
      (Sharad Agarwal via ddas)
  29. HADOOP-4523. Prevent too many tasks scheduled on a node from bringing it down by monitoring for cumulative memory usage across tasks.
      (Vinod Kumar Vavilapalli via yhemanth)
  30. HADOOP-4640. Adds an input format that can split lzo compressed text files.
      (johan)
  31. HADOOP-4666. Launch reduces only after a few maps have run in the Fair Scheduler.
      (Matei Zaharia via johan)
  32. HADOOP-4339. Remove redundant calls from FileSystem/FsShell when generating/processing ContentSummary.
      (David Phillips via cdouglas)
  33. HADOOP-2774. Add counters tracking records spilled to disk in MapTask and ReduceTask.
      (Ravi Gummadi via cdouglas)
  34. HADOOP-4513. Initialize jobs asynchronously in the capacity scheduler.
      (Sreekanth Ramakrishnan via yhemanth)
  35. HADOOP-4649. Improve abstraction for spill indices.
      (cdouglas)
  36. HADOOP-3770. Add gridmix2, an iteration on the gridmix benchmark.
      (Runping Qi via cdouglas)
  37. HADOOP-4708. Add support for dfsadmin commands in TestCLI.
      (Boris Shkolnik via cdouglas)
  38. HADOOP-4758. Add a splitter for metrics contexts to support more than one type of collector.
      (cdouglas)
  39. HADOOP-4722. Add tests for dfsadmin quota error messages.
      (Boris Shkolnik via cdouglas)
  40. HADOOP-4690. fuse-dfs - create source file/function + utils + config + main source files.
      (pete wyckoff via mahadev)
  41. HADOOP-3750. Fix and enforce module dependencies.
      (Sharad Agarwal via tomwhite)
  42. HADOOP-4747. Speed up FsShell::ls by removing redundant calls to the filesystem.
      (David Phillips via cdouglas)
  43. HADOOP-4305. Improves the blacklisting strategy, whereby, tasktrackers that are blacklisted are not given tasks to run from other jobs, subject to the following conditions (all must be met): 1) The TaskTracker has been blacklisted by at least 4 jobs (configurable) 2) The TaskTracker has been blacklisted 50% more number of times than the average (configurable) 3) The cluster has less than 50% trackers blacklisted Once in 24 hours, a TaskTracker blacklisted for all jobs is given a chance. Restarting the TaskTracker moves it out of the blacklist.
      (Amareshwari Sriramadasu via ddas)
  44. HADOOP-4688. Modify the MiniMRDFSSort unit test to spill multiple times, exercising the map-side merge code.
      (cdouglas)
  45. HADOOP-4737. Adds the KILLED notification when jobs get killed.
      (Amareshwari Sriramadasu via ddas)
  46. HADOOP-4728. Add a test exercising different namenode configurations.
      (Boris Shkolnik via cdouglas)
  47. HADOOP-4807. Adds JobClient commands to get the active/blacklisted tracker names. Also adds commands to display running/completed task attempt IDs.
      (ddas)
  48. HADOOP-4699. Remove checksum validation from map output servlet.
      (cdouglas)
  49. HADOOP-4838. Added a registry to automate metrics and mbeans management.
      (Sanjay Radia via acmurthy)
  50. HADOOP-3136. Fixed the default scheduler to assign multiple tasks to each tasktracker per heartbeat, when feasible. To ensure locality isn't hurt too badly, the scheudler will not assign more than one off-switch task per heartbeat. The heartbeat interval is also halved since the task-tracker is fixed to no longer send out heartbeats on each task completion. A slow-start for scheduling reduces is introduced to ensure that reduces aren't started till sufficient number of maps are done, else reduces of jobs whose maps aren't scheduled might swamp the cluster. Configuration changes to mapred-default.xml: add mapred.reduce.slowstart.completed.maps
      (acmurthy)
  51. HADOOP-4545. Add example and test case of secondary sort for the reduce.
      (omalley)
  52. HADOOP-4753. Refactor gridmix2 to reduce code duplication.
      (cdouglas)
  53. HADOOP-4909. Fix Javadoc and make some of the API more consistent in their use of the JobContext instead of Configuration.
      (omalley)
  54. HADOOP-4830. Add end-to-end test cases for testing queue capacities.
      (Vinod Kumar Vavilapalli via yhemanth)
  55. HADOOP-4980. Improve code layout of capacity scheduler to make it easier to fix some blocker bugs.
      (Vivek Ratan via yhemanth)
  56. HADOOP-4916. Make user/location of Chukwa installation configurable by an external properties file.
      (Eric Yang via cdouglas)
  57. HADOOP-4950. Make the CompressorStream, DecompressorStream, BlockCompressorStream, and BlockDecompressorStream public to facilitate non-Hadoop codecs.
      (omalley)
  58. HADOOP-4843. Collect job history and configuration in Chukwa.
      (Eric Yang via cdouglas)
  59. HADOOP-5030. Build Chukwa RPM to install into configured directory.
      (Eric Yang via cdouglas)
  60. HADOOP-4828. Updates documents to do with configuration (HADOOP-4631).
      (Sharad Agarwal via ddas)
  61. HADOOP-4939. Adds a test that would inject random failures for tasks in large jobs and would also inject TaskTracker failures.
      (ddas)
  62. HADOOP-4920. Stop storing Forrest output in Subversion.
      (cutting)
  63. HADOOP-4944. A configuration file can include other configuration files.
      (Rama Ramasamy via dhruba)
  64. HADOOP-4804. Provide Forrest documentation for the Fair Scheduler.
      (Sreekanth Ramakrishnan via yhemanth)
  65. HADOOP-5248. A testcase that checks for the existence of job directory after the job completes. Fails if it exists.
      (ddas)
  66. HADOOP-4664. Introduces multiple job initialization threads, where the number of threads are configurable via mapred.jobinit.threads.
      (Matei Zaharia and Jothi Padmanabhan via ddas)
  67. HADOOP-4191. Adds a testcase for JobHistory.
      (Ravi Gummadi via ddas)
  68. HADOOP-5466. Change documenation CSS style for headers and code.
      (Corinne Chandel via szetszwo)
  69. HADOOP-5275. Add ivy directory and files to built tar.
      (Giridharan Kesavan via nigel)
  70. HADOOP-5468. Add sub-menus to forrest documentation and make some minor edits.
      (Corinne Chandel via szetszwo)
  71. HADOOP-5437. Fix TestMiniMRDFSSort to properly test jvm-reuse.
      (omalley)
  72. HADOOP-5521. Removes dependency of TestJobInProgress on RESTART_COUNT JobHistory tag.
      (Ravi Gummadi via ddas)
  73. HADOOP-5714. Add a metric for NameNode getFileInfo operation.
      (Jakob Homan via szetszwo)
- OPTIMIZATIONS (2)
  1. HADOOP-3293. Fixes FileInputFormat to do provide locations for splits based on the rack/host that has the most number of bytes.
     (Jothi Padmanabhan via ddas)
  2. HADOOP-4683. Fixes Reduce shuffle scheduler to invoke getMapCompletionEvents in a separate thread.
     (Jothi Padmanabhan via ddas)
- BUG FIXES (158)
  1. HADOOP-5379. CBZip2InputStream to throw IOException on data crc error.
     (Rodrigo Schmidt via zshao)
  2. HADOOP-5326. Fixes CBZip2OutputStream data corruption problem.
     (Rodrigo Schmidt via zshao)
  3. HADOOP-4204. Fix findbugs warnings related to unused variables, naive Number subclass instantiation, Map iteration, and badly scoped inner classes.
     (Suresh Srinivas via cdouglas)
  4. HADOOP-4207. Update derby jar file to release 10.4.2 release.
     (Prasad Chakka via dhruba)
  5. HADOOP-4325. SocketInputStream.read() should return -1 in case EOF.
     (Raghu Angadi)
  6. HADOOP-4408. FsAction functions need not create new objects.
     (cdouglas)
  7. HADOOP-4440. TestJobInProgressListener tests for jobs killed in queued state
     (Amar Kamat via ddas)
  8. HADOOP-4346. Implement blocking connect so that Hadoop is not affected by selector problem with JDK default implementation.
     (Raghu Angadi)
  9. HADOOP-4388. If there are invalid blocks in the transfer list, Datanode should handle them and keep transferring the remaining blocks.
     (Suresh Srinivas via szetszwo)
  10. HADOOP-4587. Fix a typo in Mapper javadoc.
      (Koji Noguchi via szetszwo)
  11. HADOOP-4530. In fsck, HttpServletResponse sendError fails with IllegalStateException.
      (hairong)
  12. HADOOP-4377. Fix a race condition in directory creation in NativeS3FileSystem.
      (David Phillips via cdouglas)
  13. HADOOP-4621. Fix javadoc warnings caused by duplicate jars.
      (Kan Zhang via cdouglas)
  14. HADOOP-4566. Deploy new hive code to support more types.
      (Zheng Shao via dhruba)
  15. HADOOP-4571. Add chukwa conf files to svn:ignore list.
      (Eric Yang via szetszwo)
  16. HADOOP-4589. Correct PiEstimator output messages and improve the code readability.
      (szetszwo)
  17. HADOOP-4650. Correct a mismatch between the default value of local.cache.size in the config and the source.
      (Jeff Hammerbacher via cdouglas)
  18. HADOOP-4606. Fix cygpath error if the log directory does not exist.
      (szetszwo via omalley)
  19. HADOOP-4141. Fix bug in ScriptBasedMapping causing potential infinite loop on misconfigured hadoop-site.
      (Aaron Kimball via tomwhite)
  20. HADOOP-4691. Correct a link in the javadoc of IndexedSortable.
      (szetszwo)
  21. HADOOP-4598. '-setrep' command skips under-replicated blocks.
      (hairong)
  22. HADOOP-4429. Set defaults for user, group in UnixUserGroupInformation so login fails more predictably when misconfigured.
      (Alex Loddengaard via cdouglas)
  23. HADOOP-4676. Fix broken URL in blacklisted tasktrackers page.
      (Amareshwari Sriramadasu via cdouglas)
  24. HADOOP-3422 Ganglia counter metrics are all reported with the metric name "value", so the counter values can not be seen.
      (Jason Attributor and Brian Bockelman via stack)
  25. HADOOP-4704. Fix javadoc typos "the the".
      (szetszwo)
  26. HADOOP-4677. Fix semantics of FileSystem::getBlockLocations to return meaningful values.
      (Hong Tang via cdouglas)
  27. HADOOP-4669. Use correct operator when evaluating whether access time is enabled
      (Dhruba Borthakur via cdouglas)
  28. HADOOP-4732. Pass connection and read timeouts in the correct order when setting up fetch in reduce.
      (Amareshwari Sriramadasu via cdouglas)
  29. HADOOP-4558. Fix capacity reclamation in capacity scheduler.
      (Amar Kamat via yhemanth)
  30. HADOOP-4770. Fix rungridmix_2 script to work with RunJar.
      (cdouglas)
  31. HADOOP-4738. When using git, the saveVersion script will use only the commit hash for the version and not the message, which requires escaping.
      (cdouglas)
  32. HADOOP-4576. Show pending job count instead of task count in the UI per queue in capacity scheduler.
      (Sreekanth Ramakrishnan via yhemanth)
  33. HADOOP-4623. Maintain running tasks even if speculative execution is off.
      (Amar Kamat via yhemanth)
  34. HADOOP-4786. Fix broken compilation error in TestTrackerBlacklistAcrossJobs.
      (yhemanth)
  35. HADOOP-4785. Fixes theJobTracker heartbeat to not make two calls to System.currentTimeMillis().
      (Amareshwari Sriramadasu via ddas)
  36. HADOOP-4792. Add generated Chukwa configuration files to version control ignore lists.
      (cdouglas)
  37. HADOOP-4796. Fix Chukwa test configuration, remove unused components.
      (Eric Yang via cdouglas)
  38. HADOOP-4708. Add binaries missed in the initial checkin for Chukwa.
      (Eric Yang via cdouglas)
  39. HADOOP-4805. Remove black list collector from Chukwa Agent HTTP Sender.
      (Eric Yang via cdouglas)
  40. HADOOP-4837. Move HADOOP_CONF_DIR configuration to chukwa-env.sh
      (Jerome Boulon via cdouglas)
  41. HADOOP-4825. Use ps instead of jps for querying process status in Chukwa.
      (Eric Yang via cdouglas)
  42. HADOOP-4844. Fixed javadoc for org.apache.hadoop.fs.permission.AccessControlException to document that it's deprecated in favour of org.apache.hadoop.security.AccessControlException.
      (acmurthy)
  43. HADOOP-4706. Close the underlying output stream in IFileOutputStream::close.
      (Jothi Padmanabhan via cdouglas)
  44. HADOOP-4855. Fixed command-specific help messages for refreshServiceAcl in DFSAdmin and MRAdmin.
      (acmurthy)
  45. HADOOP-4820. Remove unused method FSNamesystem::deleteInSafeMode.
      (Suresh Srinivas via cdouglas)
  46. HADOOP-4698. Lower io.sort.mb to 10 in the tests and raise the junit memory limit to 512m from 256m.
      (Nigel Daley via cdouglas)
  47. HADOOP-4860. Split TestFileTailingAdapters into three separate tests to avoid contention.
      (Eric Yang via cdouglas)
  48. HADOOP-3921. Fixed clover (code coverage) target to work with JDK 6.
      (tomwhite via nigel)
  49. HADOOP-4845. Modify the reduce input byte counter to record only the compressed size and add a human-readable label.
      (Yongqiang He via cdouglas)
  50. HADOOP-4458. Add a test creating symlinks in the working directory.
      (Amareshwari Sriramadasu via cdouglas)
  51. HADOOP-4879. Fix org.apache.hadoop.mapred.Counters to correctly define Object.equals rather than depend on contentEquals api.
      (omalley via acmurthy)
  52. HADOOP-4791. Fix rpm build process for Chukwa.
      (Eric Yang via cdouglas)
  53. HADOOP-4771. Correct initialization of the file count for directories with quotas.
      (Ruyue Ma via shv)
  54. HADOOP-4878. Fix eclipse plugin classpath file to point to ivy's resolved lib directory and added the same to test-patch.sh.
      (Giridharan Kesavan via acmurthy)
  55. HADOOP-4774. Fix default values of some capacity scheduler configuration items which would otherwise not work on a fresh checkout.
      (Sreekanth Ramakrishnan via yhemanth)
  56. HADOOP-4876. Fix capacity scheduler reclamation by updating count of pending tasks correctly.
      (Sreekanth Ramakrishnan via yhemanth)
  57. HADOOP-4849. Documentation for Service Level Authorization implemented in HADOOP-4348.
      (acmurthy)
  58. HADOOP-4827. Replace Consolidator with Aggregator macros in Chukwa
      (Eric Yang via cdouglas)
  59. HADOOP-4894. Correctly parse ps output in Chukwa jettyCollector.sh.
      (Ari Rabkin via cdouglas)
  60. HADOOP-4892. Close fds out of Chukwa ExecPlugin.
      (Ari Rabkin via cdouglas)
  61. HADOOP-4889. Fix permissions in RPM packaging.
      (Eric Yang via cdouglas)
  62. HADOOP-4869. Fixes the TT-JT heartbeat to have an explicit flag for restart apart from the initialContact flag that there was earlier.
      (Amareshwari Sriramadasu via ddas)
  63. HADOOP-4716. Fixes ReduceTask.java to clear out the mapping between hosts and MapOutputLocation upon a JT restart
      (Amar Kamat via ddas)
  64. HADOOP-4880. Removes an unnecessary testcase from TestJobTrackerRestart.
      (Amar Kamat via ddas)
  65. HADOOP-4924. Fixes a race condition in TaskTracker re-init.
      (ddas)
  66. HADOOP-4854. Read reclaim capacity interval from capacity scheduler configuration.
      (Sreekanth Ramakrishnan via yhemanth)
  67. HADOOP-4896. HDFS Fsck does not load HDFS configuration.
      (Raghu Angadi)
  68. HADOOP-4956. Creates TaskStatus for failed tasks with an empty Counters object instead of null.
      (ddas)
  69. HADOOP-4979. Fix capacity scheduler to block cluster for failed high RAM requirements across task types.
      (Vivek Ratan via yhemanth)
  70. HADOOP-4949. Fix native compilation.
      (Chris Douglas via acmurthy)
  71. HADOOP-4787. Fixes the testcase TestTrackerBlacklistAcrossJobs which was earlier failing randomly.
      (Amareshwari Sriramadasu via ddas)
  72. HADOOP-4914. Add description fields to Chukwa init.d scripts
      (Eric Yang via cdouglas)
  73. HADOOP-4884. Make tool tip date format match standard HICC format.
      (Eric Yang via cdouglas)
  74. HADOOP-4925. Make Chukwa sender properties configurable.
      (Ari Rabkin via cdouglas)
  75. HADOOP-4947. Make Chukwa command parsing more forgiving of whitespace.
      (Ari Rabkin via cdouglas)
  76. HADOOP-5026. Make chukwa/bin scripts executable in repository.
      (Andy Konwinski via cdouglas)
  77. HADOOP-4977. Fix a deadlock between the reclaimCapacity and assignTasks in capacity scheduler.
      (Vivek Ratan via yhemanth)
  78. HADOOP-4988. Fix reclaim capacity to work even when there are queues with no capacity.
      (Vivek Ratan via yhemanth)
  79. HADOOP-5065. Remove generic parameters from argument to setIn/OutputFormatClass so that it works with SequenceIn/OutputFormat.
      (cdouglas via omalley)
  80. HADOOP-4818. Pass user config to instrumentation API.
      (Eric Yang via cdouglas)
  81. HADOOP-4993. Fix Chukwa agent configuration and startup to make it both more modular and testable.
      (Ari Rabkin via cdouglas)
  82. HADOOP-5048. Fix capacity scheduler to correctly cleanup jobs that are killed after initialization, but before running.
      (Sreekanth Ramakrishnan via yhemanth)
  83. HADOOP-4671. Mark loop control variables shared between threads as volatile.
      (cdouglas)
  84. HADOOP-5079. HashFunction inadvertently destroys some randomness
      (Jonathan Ellis via stack)
  85. HADOOP-4999. A failure to write to FsEditsLog results in IndexOutOfBounds exception.
      (Boris Shkolnik via rangadi)
  86. HADOOP-5139. Catch IllegalArgumentException during metrics registration in RPC.
      (Hairong Kuang via szetszwo)
  87. HADOOP-5085. Copying a file to local with Crc throws an exception.
      (hairong)
  88. HADOOP-4759. Removes temporary output directory for failed and killed tasks by launching special CLEANUP tasks for the same.
      (Amareshwari Sriramadasu via ddas)
  89. HADOOP-5211. Fix check for job completion in TestSetupAndCleanupFailure.
      (enis)
  90. HADOOP-5254. The Configuration class should be able to work with XML parsers that do not support xmlinclude.
      (Steve Loughran via dhruba)
  91. HADOOP-4692. Namenode in infinite loop for replicating/deleting corrupt blocks.
      (hairong)
  92. HADOOP-5255. Fix use of Math.abs to avoid overflow.
      (Jonathan Ellis via cdouglas)
  93. HADOOP-5269. Fixes a problem to do with tasktracker holding on to FAILED_UNCLEAN or KILLED_UNCLEAN tasks forever.
      (Amareshwari Sriramadasu via ddas)
  94. HADOOP-5214. Fixes a ConcurrentModificationException while the Fairshare Scheduler accesses the tasktrackers stored by the JobTracker.
      (Rahul Kumar Singh via yhemanth)
  95. HADOOP-5233. Addresses the three issues - Race condition in updating status, NPE in TaskTracker task localization when the conf file is missing (HADOOP-5234) and NPE in handling KillTaskAction of a cleanup task (HADOOP-5235).
      (Amareshwari Sriramadasu via ddas)
  96. HADOOP-5247. Introduces a broadcast of KillJobAction to all trackers when a job finishes. This fixes a bunch of problems to do with NPE when a completed job is not in memory and a tasktracker comes to the jobtracker with a status report of a task belonging to that job.
      (Amar Kamat via ddas)
  97. HADOOP-5282. Fixed job history logs for task attempts that are failed by the JobTracker, say due to lost task trackers.
      (Amar Kamat via yhemanth)
  98. HADOOP-4963. Fixes a logging to do with getting the location of map output file.
      (Amareshwari Sriramadasu via ddas)
  99. HADOOP-5292. Fix NPE in KFS::getBlockLocations.
      (Sriram Rao via lohit)
  100. HADOOP-5241. Fixes a bug in disk-space resource estimation. Makes the estimation formula linear where blowUp = Total-Output/Total-Input.
       (Sharad Agarwal via ddas)
  101. HADOOP-5142. Fix MapWritable#putAll to store key/value classes.
       (Do??acan G??ney via enis)
  102. HADOOP-4744. Workaround for jetty6 returning -1 when getLocalPort is invoked on the connector. The workaround patch retries a few times before failing.
       (Jothi Padmanabhan via yhemanth)
  103. HADOOP-5280. Adds a check to prevent a task state transition from FAILED to any of UNASSIGNED, RUNNING, COMMIT_PENDING or SUCCEEDED.
       (ddas)
  104. HADOOP-5272. Fixes a problem to do with detecting whether an attempt is the first attempt of a Task. This affects JobTracker restart.
       (Amar Kamat via ddas)
  105. HADOOP-5306. Fixes a problem to do with logging/parsing the http port of a lost tracker. Affects JobTracker restart.
       (Amar Kamat via ddas)
  106. HADOOP-5111. Fix Job::set* methods to work with generics.
       (cdouglas)
  107. HADOOP-5274. Fix gridmix2 dependency on wordcount example.
       (cdouglas)
  108. HADOOP-5145. Balancer sometimes runs out of memory after running days or weeks.
       (hairong)
  109. HADOOP-5338. Fix jobtracker restart to clear task completion events cached by tasktrackers forcing them to fetch all events afresh, thus avoiding missed task completion events on the tasktrackers.
       (Amar Kamat via yhemanth)
  110. HADOOP-4695. Change TestGlobalFilter so that it allows a web page to be filtered more than once for a single access.
       (Kan Zhang via szetszwo)
  111. HADOOP-5298. Change TestServletFilter so that it allows a web page to be filtered more than once for a single access.
       (szetszwo)
  112. HADOOP-5432. Disable ssl during unit tests in hdfsproxy, as it is unused and causes failures.
       (cdouglas)
  113. HADOOP-5416. Correct the shell command "fs -test" forrest doc description.
       (Ravi Phulari via szetszwo)
  114. HADOOP-5327. Fixed job tracker to remove files from system directory on ACL check failures and also check ACLs on restart.
       (Amar Kamat via yhemanth)
  115. HADOOP-5395. Change the exception message when a job is submitted to an invalid queue.
       (Rahul Kumar Singh via yhemanth)
  116. HADOOP-5276. Fixes a problem to do with updating the start time of a task when the tracker that ran the task is lost.
       (Amar Kamat via ddas)
  117. HADOOP-5278. Fixes a problem to do with logging the finish time of a task during recovery (after a JobTracker restart).
       (Amar Kamat via ddas)
  118. HADOOP-5490. Fixes a synchronization problem in the EagerTaskInitializationListener class.
       (Jothi Padmanabhan via ddas)
  119. HADOOP-5493. The shuffle copier threads return the codecs back to the pool when the shuffle completes.
       (Jothi Padmanabhan via ddas)
  120. HADOOP-5505. Fix JspHelper initialization in the context of MiniDFSCluster.
       (Raghu Angadi)
  121. HADOOP-5414. Fixes IO exception while executing hadoop fs -touchz fileName by making sure that lease renewal thread exits before dfs client exits.
       (hairong)
  122. HADOOP-5103. FileInputFormat now reuses the clusterMap network topology object and that brings down the log messages in the JobClient to do with NetworkTopology.add significantly.
       (Jothi Padmanabhan via ddas)
  123. HADOOP-5483. Fixes a problem in the Directory Cleanup Thread due to which TestMiniMRWithDFS sometimes used to fail.
       (ddas)
  124. HADOOP-5281. Prevent sharing incompatible ZlibCompressor instances between GzipCodec and DefaultCodec.
       (cdouglas)
  125. HADOOP-5463. Balancer throws "Not a host:port pair" unless port is specified in fs.default.name.
       (Stuart White via hairong)
  126. HADOOP-5514. Fix JobTracker metrics and add metrics for wating, failed tasks.
       (cdouglas)
  127. HADOOP-5516. Fix NullPointerException in TaskMemoryManagerThread that comes when monitored processes disappear when the thread is running.
       (Vinod Kumar Vavilapalli via yhemanth)
  128. HADOOP-5382. Support combiners in the new context object API.
       (omalley)
  129. HADOOP-5471. Fixes a problem to do with updating the log.index file in the case where a cleanup task is run.
       (Amareshwari Sriramadasu via ddas)
  130. HADOOP-5534. Fixed a deadlock in Fair scheduler's servlet.
       (Rahul Kumar Singh via yhemanth)
  131. HADOOP-5328. Fixes a problem in the renaming of job history files during job recovery. Amar Kamat via ddas)
  132. HADOOP-5417. Don't ignore InterruptedExceptions that happen when calling into rpc.
       (omalley)
  133. HADOOP-5320. Add a close() in TestMapReduceLocal.
       (Jothi Padmanabhan via szetszwo)
  134. HADOOP-5520. Fix a typo in disk quota help message.
       (Ravi Phulari via szetszwo)
  135. HADOOP-5519. Remove claims from mapred-default.xml that prime numbers of tasks are helpful.
       (Owen O'Malley via szetszwo)
  136. HADOOP-5484. TestRecoveryManager fails wtih FileAlreadyExistsException.
       (Amar Kamat via hairong)
  137. HADOOP-5564. Limit the JVM heap size in the java command for initializing JAVA_PLATFORM.
       (Suresh Srinivas via szetszwo)
  138. HADOOP-5565. Add API for failing/finalized jobs to the JT metrics instrumentation.
       (Jerome Boulon via cdouglas)
  139. HADOOP-5390. Remove duplicate jars from tarball, src from binary tarball added by hdfsproxy.
       (Zhiyong Zhang via cdouglas)
  140. HADOOP-5066. Building binary tarball should not build docs/javadocs, copy src, or run jdiff.
       (Giridharan Kesavan via cdouglas)
  141. HADOOP-5459. Fix undetected CRC errors where intermediate output is closed before it has been completely consumed.
       (cdouglas)
  142. HADOOP-5571. Remove widening primitive conversion in TupleWritable mask manipulation.
       (Jingkei Ly via cdouglas)
  143. HADOOP-5588. Remove an unnecessary call to listStatus(..) in FileSystem.globStatusInternal(..).
       (Hairong Kuang via szetszwo)
  144. HADOOP-5473. Solves a race condition in killing a task - the state is KILLED if there is a user request pending to kill the task and the TT reported the state as SUCCESS.
       (Amareshwari Sriramadasu via ddas)
  145. HADOOP-5576. Fix LocalRunner to work with the new context object API in mapreduce.
       (Tom White via omalley)
  146. HADOOP-4374. Installs a shutdown hook in the Task JVM so that log.index is updated before the JVM exits. Also makes the update to log.index atomic.
       (Ravi Gummadi via ddas)
  147. HADOOP-5577. Add a verbose flag to mapreduce.Job.waitForCompletion to get the running job's information printed to the user's stdout as it runs.
       (omalley)
  148. HADOOP-5607. Fix NPE in TestCapacityScheduler.
       (cdouglas)
  149. HADOOP-5605. All the replicas incorrectly got marked as corrupt.
       (hairong)
  150. HADOOP-5337. JobTracker, upon restart, now waits for the TaskTrackers to join back before scheduling new tasks. This fixes race conditions associated with greedy scheduling as was the case earlier.
       (Amar Kamat via ddas)
  151. HADOOP-5227. Fix distcp so -update and -delete can be meaningfully combined. (Tsz Wo (Nicholas), SZE via cdouglas)
  152. HADOOP-5305. Increase number of files and print debug messages in TestCopyFiles.
       (szetszwo)
  153. HADOOP-5548. Add synchronization for JobTracker methods in RecoveryManager.
       (Amareshwari Sriramadasu via sharad)
  154. HADOOP-3810. NameNode seems unstable on a cluster with little space left.
       (hairong)
  155. HADOOP-5068. Fix NPE in TestCapacityScheduler.
       (Vinod Kumar Vavilapalli via szetszwo)
  156. HADOOP-5585. Clear FileSystem statistics between tasks when jvm-reuse is enabled.
       (omalley)
  157. HADOOP-5394. JobTracker might schedule 2 attempts of the same task with the same attempt id across restarts.
       (Amar Kamat via sharad)
  158. HADOOP-5645. After HADOOP-4920 we need a place to checkin releasenotes.html.
       (nigel)

## Older Releases

### Release 0.19.2 - Unreleased

- BUG FIXES (27)
  1. HADOOP-5154. Fixes a deadlock in the fairshare scheduler.
     (Matei Zaharia via yhemanth)
  2. HADOOP-5146. Fixes a race condition that causes LocalDirAllocator to miss files.
     (Devaraj Das via yhemanth)
  3. HADOOP-4638. Fixes job recovery to not crash the job tracker for problems with a single job file.
     (Amar Kamat via yhemanth)
  4. HADOOP-5384. Fix a problem that DataNodeCluster creates blocks with generationStamp == 1.
     (szetszwo)
  5. HADOOP-5376. Fixes the code handling lost tasktrackers to set the task state to KILLED_UNCLEAN only for relevant type of tasks.
     (Amareshwari Sriramadasu via yhemanth)
  6. HADOOP-5285. Fixes the issues - (1) obtainTaskCleanupTask checks whether job is inited before trying to lock the JobInProgress (2) Moves the CleanupQueue class outside the TaskTracker and makes it a generic class that is used by the JobTracker also for deleting the paths on the job's output fs. (3) Moves the references to completedJobStore outside the block where the JobTracker is locked.
     (ddas)
  7. HADOOP-5392. Fixes a problem to do with JT crashing during recovery when the job files are garbled.
     (Amar Kamat vi ddas)
  8. HADOOP-5332. Appending to files is not allowed (by default) unless dfs.support.append is set to true.
     (dhruba)
  9. HADOOP-5333. libhdfs supports appending to files.
     (dhruba)
  10. HADOOP-3998. Fix dfsclient exception when JVM is shutdown.
      (dhruba)
  11. HADOOP-5440. Fixes a problem to do with removing a taskId from the list of taskIds that the TaskTracker's TaskMemoryManager manages.
      (Amareshwari Sriramadasu via ddas)
  12. HADOOP-5446. Restore TaskTracker metrics.
      (cdouglas)
  13. HADOOP-5449. Fixes the history cleaner thread.
      (Amareshwari Sriramadasu via ddas)
  14. HADOOP-5479. NameNode should not send empty block replication request to DataNode.
      (hairong)
  15. HADOOP-5259. Job with output hdfs:/user/<username>/outputpath (no authority) fails with Wrong FS.
      (Doug Cutting via hairong)
  16. HADOOP-5522. Documents the setup/cleanup tasks in the mapred tutorial.
      (Amareshwari Sriramadasu via ddas)
  17. HADOOP-5549. ReplicationMonitor should schedule both replication and deletion work in one iteration.
      (hairong)
  18. HADOOP-5554. DataNodeCluster and CreateEditsLog should create blocks with the same generation stamp value.
      (hairong via szetszwo)
  19. HADOOP-5231. Clones the TaskStatus before passing it to the JobInProgress.
      (Amareshwari Sriramadasu via ddas)
  20. HADOOP-4719. Fix documentation of 'ls' format for FsShell.
      (Ravi Phulari via cdouglas)
  21. HADOOP-5374. Fixes a NPE problem in getTasksToSave method.
      (Amareshwari Sriramadasu via ddas)
  22. HADOOP-4780. Cache the size of directories in DistributedCache, avoiding long delays in recalculating it.
      (He Yongqiang via cdouglas)
  23. HADOOP-5551. Prevent directory destruction on file create.
      (Brian Bockelman via shv)
  24. HADOOP-5671. Fix FNF exceptions when copying from old versions of HftpFileSystem. (Tsz Wo (Nicholas), SZE via cdouglas)
  25. HADOOP-5579. Set errno correctly in libhdfs for permission, quota, and FNF conditions.
      (Brian Bockelman via cdouglas)
  26. HADOOP-5816. Fixes a problem in the KeyFieldBasedComparator to do with ArrayIndexOutOfBounds exception.
      (He Yongqiang via ddas)
  27. HADOOP-5951. Add Apache license header to StorageInfo.java.
      (Suresh Srinivas via szetszwo)

### Release 0.19.1 - 2009-02-23

- IMPROVEMENTS (4)
  1. HADOOP-4739. Fix spelling and grammar, improve phrasing of some sections in mapred tutorial.
     (Vivek Ratan via cdouglas)
  2. HADOOP-3894. DFSClient logging improvements.
     (Steve Loughran via shv)
  3. HADOOP-5126. Remove empty file BlocksWithLocations.java
     (shv)
  4. HADOOP-5127. Remove public methods in FSDirectory.
     (Jakob Homan via shv)
- BUG FIXES (27)
  1. HADOOP-4697. Fix getBlockLocations in KosmosFileSystem to handle multiple blocks correctly.
     (Sriram Rao via cdouglas)
  2. HADOOP-4420. Add null checks for job, caused by invalid job IDs.
     (Aaron Kimball via tomwhite)
  3. HADOOP-4632. Fix TestJobHistoryVersion to use test.build.dir instead of the current workding directory for scratch space.
     (Amar Kamat via cdouglas)
  4. HADOOP-4508. Fix FSDataOutputStream.getPos() for append.
     (dhruba via szetszwo)
  5. HADOOP-4727. Fix a group checking bug in fill_stat_structure(...) in fuse-dfs.
     (Brian Bockelman via szetszwo)
  6. HADOOP-4836. Correct typos in mapred related documentation.
     (Jord? Polo via szetszwo)
  7. HADOOP-4821. Usage description in the Quotas guide documentations are incorrect.
     (Boris Shkolnik via hairong)
  8. HADOOP-4847. Moves the loading of OutputCommitter to the Task.
     (Amareshwari Sriramadasu via ddas)
  9. HADOOP-4966. Marks completed setup tasks for removal.
     (Amareshwari Sriramadasu via ddas)
  10. HADOOP-4982. TestFsck should run in Eclipse.
      (shv)
  11. HADOOP-5008. TestReplication#testPendingReplicationRetry leaves an opened fd unclosed.
      (hairong)
  12. HADOOP-4906. Fix TaskTracker OOM by keeping a shallow copy of JobConf in TaskTracker.TaskInProgress.
      (Sharad Agarwal via acmurthy)
  13. HADOOP-4918. Fix bzip2 compression to work with Sequence Files. (Zheng Shao via dhruba).
  14. HADOOP-4965. TestFileAppend3 should close FileSystem.
      (shv)
  15. HADOOP-4967. Fixes a race condition in the JvmManager to do with killing tasks.
      (ddas)
  16. HADOOP-5009. DataNode#shutdown sometimes leaves data block scanner verification log unclosed.
      (hairong)
  17. HADOOP-5086. Use the appropriate FileSystem for trash URIs.
      (cdouglas)
  18. HADOOP-4955. Make DBOutputFormat us column names from setOutput().
      (Kevin Peterson via enis)
  19. HADOOP-4862. Minor : HADOOP-3678 did not remove all the cases of spurious IOExceptions logged by DataNode.
      (Raghu Angadi)
  20. HADOOP-5034. NameNode should send both replication and deletion requests to DataNode in one reply to a heartbeat.
      (hairong)
  21. HADOOP-5156. TestHeartbeatHandling uses MiiDFSCluster.getNamesystem() which does not exit in branch 0.19 and 0.20.
      (hairong)
  22. HADOOP-5161. Accepted sockets do not get placed in DataXceiverServer#childSockets.
      (hairong)
  23. HADOOP-5193. Correct calculation of edits modification time.
      (shv)
  24. HADOOP-4494. Allow libhdfs to append to files.
      (Pete Wyckoff via dhruba)
  25. HADOOP-5166. Fix JobTracker restart to work when ACLs are configured for the JobTracker. (Amar Kamat via yhemanth).
  26. HADOOP-5067. Fixes TaskInProgress.java to keep track of count of failed and killed tasks correctly.
      (Amareshwari Sriramadasu via ddas)
  27. HADOOP-4760. HDFS streams should not throw exceptions when closed twice.
      (enis)

### Release 0.19.0 - 2008-11-18

- INCOMPATIBLE CHANGES (23)
  1. HADOOP-3595. Remove deprecated methods for mapred.combine.once functionality, which was necessary to providing backwards compatible combiner semantics for 0.18.
     (cdouglas via omalley)
  2. HADOOP-3667. Remove the following deprecated methods from JobConf: addInputPath(Path) getInputPaths() getMapOutputCompressionType() getOutputPath() getSystemDir() setInputPath(Path) setMapOutputCompressionType(CompressionType style) setOutputPath(Path)
     (Amareshwari Sriramadasu via omalley)
  3. HADOOP-3652. Remove deprecated class OutputFormatBase.
     (Amareshwari Sriramadasu via cdouglas)
  4. HADOOP-2885. Break the hadoop.dfs package into separate packages under hadoop.hdfs that reflect whether they are client, server, protocol, etc. DistributedFileSystem and DFSClient have moved and are now considered package private.
     (Sanjay Radia via omalley)
  5. HADOOP-2325. Require Java 6.
     (cutting)
  6. HADOOP-372. Add support for multiple input paths with a different InputFormat and Mapper for each path.
     (Chris Smith via tomwhite)
  7. HADOOP-1700. Support appending to file in HDFS.
     (dhruba)
  8. HADOOP-3792. Make FsShell -test consistent with unix semantics, returning zero for true and non-zero for false.
     (Ben Slusky via cdouglas)
  9. HADOOP-3664. Remove the deprecated method InputFormat.validateInput, which is no longer needed.
     (tomwhite via omalley)
  10. HADOOP-3549. Give more meaningful errno's in libhdfs. In particular, EACCES is returned for permission problems.
      (Ben Slusky via omalley)
  11. HADOOP-4036. ResourceStatus was added to TaskTrackerStatus by HADOOP-3759, so increment the InterTrackerProtocol version.
      (Hemanth Yamijala via omalley)
  12. HADOOP-3150. Moves task promotion to tasks. Defines a new interface for committing output files. Moves job setup to jobclient, and moves jobcleanup to a separate task.
      (Amareshwari Sriramadasu via ddas)
  13. HADOOP-3446. Keep map outputs in memory during the reduce. Remove fs.inmemory.size.mb and replace with properties defining in memory map output retention during the shuffle and reduce relative to maximum heap usage.
      (cdouglas)
  14. HADOOP-3245. Adds the feature for supporting JobTracker restart. Running jobs can be recovered from the history file. The history file format has been modified to support recovery. The task attempt ID now has the JobTracker start time to disinguish attempts of the same TIP across restarts.
      (Amar Ramesh Kamat via ddas)
  15. HADOOP-4007. REMOVE DFSFileInfo - FileStatus is sufficient.
      (Sanjay Radia via hairong)
  16. HADOOP-3722. Fixed Hadoop Streaming and Hadoop Pipes to use the Tool interface and GenericOptionsParser.
      (Enis Soztutar via acmurthy)
  17. HADOOP-2816. Cluster summary at name node web reports the space utilization as: Configured Capacity: capacity of all the data directories - Reserved space Present Capacity: Space available for dfs,i.e. remaining+used space DFS Used%: DFS used space/Present Capacity
      (Suresh Srinivas via hairong)
  18. HADOOP-3938. Disk space quotas for HDFS. This is similar to namespace quotas in 0.18.
      (rangadi)
  19. HADOOP-4293. Make Configuration Writable and remove unreleased WritableJobConf. Configuration.write is renamed to writeXml.
      (omalley)
  20. HADOOP-4281. Change dfsadmin to report available disk space in a format consistent with the web interface as defined in HADOOP-2816.
      (Suresh Srinivas via cdouglas)
  21. HADOOP-4430. Further change the cluster summary at name node web that was changed in HADOOP-2816: Non DFS Used - This indicates the disk space taken by non DFS file from the Configured capacity DFS Used % - DFS Used % of Configured Capacity DFS Remaining % - Remaing % Configured Capacity available for DFS use DFS command line report reflects the same change. Config parameter dfs.datanode.du.pct is no longer used and is removed from the hadoop-default.xml.
      (Suresh Srinivas via hairong)
  22. HADOOP-4116. Balancer should provide better resource management.
      (hairong)
  23. HADOOP-4599. BlocksMap and BlockInfo made package private.
      (shv)
- NEW FEATURES (39)
  1. HADOOP-3341. Allow streaming jobs to specify the field separator for map and reduce input and output. The new configuration values are: stream.map.input.field.separator stream.map.output.field.separator stream.reduce.input.field.separator stream.reduce.output.field.separator All of them default to "\t".
     (Zheng Shao via omalley)
  2. HADOOP-3479. Defines the configuration file for the resource manager in Hadoop. You can configure various parameters related to scheduling, such as queues and queue properties here. The properties for a queue follow a naming convention,such as, hadoop.rm.queue.queue-name.property-name.
     (Hemanth Yamijala via ddas)
  3. HADOOP-3149. Adds a way in which map/reducetasks can create multiple outputs.
     (Alejandro Abdelnur via ddas)
  4. HADOOP-3714. Add a new contrib, bash-tab-completion, which enables bash tab completion for the bin/hadoop script. See the README file in the contrib directory for the installation.
     (Chris Smith via enis)
  5. HADOOP-3730. Adds a new JobConf constructor that disables loading default configurations.
     (Alejandro Abdelnur via ddas)
  6. HADOOP-3772. Add a new Hadoop Instrumentation api for the JobTracker and the TaskTracker, refactor Hadoop Metrics as an implementation of the api.
     (Ari Rabkin via acmurthy)
  7. HADOOP-2302. Provides a comparator for numerical sorting of key fields.
     (ddas)
  8. HADOOP-153. Provides a way to skip bad records.
     (Sharad Agarwal via ddas)
  9. HADOOP-657. Free disk space should be modelled and used by the scheduler to make scheduling decisions.
     (Ari Rabkin via omalley)
  10. HADOOP-3719. Initial checkin of Chukwa, which is a data collection and analysis framework.
      (Jerome Boulon, Andy Konwinski, Ari Rabkin, and Eric Yang)
  11. HADOOP-3873. Add -filelimit and -sizelimit options to distcp to cap the number of files/bytes copied in a particular run to support incremental updates and mirroring. (TszWo (Nicholas), SZE via cdouglas)
  12. HADOOP-3585. FailMon package for hardware failure monitoring and analysis of anomalies.
      (Ioannis Koltsidas via dhruba)
  13. HADOOP-1480. Add counters to the C++ Pipes API.
      (acmurthy via omalley)
  14. HADOOP-3854. Add support for pluggable servlet filters in the HttpServers. (Tsz Wo (Nicholas) Sze via omalley)
  15. HADOOP-3759. Provides ability to run memory intensive jobs without affecting other running tasks on the nodes.
      (Hemanth Yamijala via ddas)
  16. HADOOP-3746. Add a fair share scheduler.
      (Matei Zaharia via omalley)
  17. HADOOP-3754. Add a thrift interface to access HDFS.
      (dhruba via omalley)
  18. HADOOP-3828. Provides a way to write skipped records to DFS.
      (Sharad Agarwal via ddas)
  19. HADOOP-3948. Separate name-node edits and fsimage directories.
      (Lohit Vijayarenu via shv)
  20. HADOOP-3939. Add an option to DistCp to delete files at the destination not present at the source. (Tsz Wo (Nicholas) Sze via cdouglas)
  21. HADOOP-3601. Add a new contrib module for Hive, which is a sql-like query processing tool that uses map/reduce.
      (Ashish Thusoo via omalley)
  22. HADOOP-3866. Added sort and multi-job updates in the JobTracker web ui.
      (Craig Weisenfluh via omalley)
  23. HADOOP-3698. Add access control to control who is allowed to submit or modify jobs in the JobTracker.
      (Hemanth Yamijala via omalley)
  24. HADOOP-1869. Support access times for HDFS files.
      (dhruba)
  25. HADOOP-3941. Extend FileSystem API to return file-checksums.
      (szetszwo)
  26. HADOOP-3581. Prevents memory intensive user tasks from taking down nodes.
      (Vinod K V via ddas)
  27. HADOOP-3970. Provides a way to recover counters written to JobHistory.
      (Amar Kamat via ddas)
  28. HADOOP-3702. Adds ChainMapper and ChainReducer classes allow composing chains of Maps and Reduces in a single Map/Reduce job, something like MAP+ / REDUCE MAP*.
      (Alejandro Abdelnur via ddas)
  29. HADOOP-3445. Add capacity scheduler that provides guaranteed capacities to queues as a percentage of the cluster.
      (Vivek Ratan via omalley)
  30. HADOOP-3992. Add a synthetic load generation facility to the test directory.
      (hairong via szetszwo)
  31. HADOOP-3981. Implement a distributed file checksum algorithm in HDFS and change DistCp to use file checksum for comparing src and dst files
      (szetszwo)
  32. HADOOP-3829. Narrown down skipped records based on user acceptable value.
      (Sharad Agarwal via ddas)
  33. HADOOP-3930. Add common interfaces for the pluggable schedulers and the cli & gui clients.
      (Sreekanth Ramakrishnan via omalley)
  34. HADOOP-4176. Implement getFileChecksum(Path) in HftpFileSystem.
      (szetszwo)
  35. HADOOP-249. Reuse JVMs across Map-Reduce Tasks. Configuration changes to hadoop-default.xml: add mapred.job.reuse.jvm.num.tasks
      (Devaraj Das via acmurthy)
  36. HADOOP-4070. Provide a mechanism in Hive for registering UDFs from the query language.
      (tomwhite)
  37. HADOOP-2536. Implement a JDBC based database input and output formats to allow Map-Reduce applications to work with databases.
      (Fredrik Hedberg and Enis Soztutar via acmurthy)
  38. HADOOP-3019. A new library to support total order partitions.
      (cdouglas via omalley)
  39. HADOOP-3924. Added a 'KILLED' job status.
      (Subramaniam Krishnan via acmurthy)
- IMPROVEMENTS (78)
  1. HADOOP-4205. hive: metastore and ql to use the refactored SerDe library.
     (zshao)
  2. HADOOP-4106. libhdfs: add time, permission and user attribute support (part 2).
     (Pete Wyckoff through zshao)
  3. HADOOP-4104. libhdfs: add time, permission and user attribute support.
     (Pete Wyckoff through zshao)
  4. HADOOP-3908. libhdfs: better error message if llibhdfs.so doesn't exist.
     (Pete Wyckoff through zshao)
  5. HADOOP-3732. Delay intialization of datanode block verification till the verification thread is started.
     (rangadi)
  6. HADOOP-1627. Various small improvements to 'dfsadmin -report' output.
     (rangadi)
  7. HADOOP-3577. Tools to inject blocks into name node and simulated data nodes for testing.
     (Sanjay Radia via hairong)
  8. HADOOP-2664. Add a lzop compatible codec, so that files compressed by lzop may be processed by map/reduce.
     (cdouglas via omalley)
  9. HADOOP-3655. Add additional ant properties to control junit.
     (Steve Loughran via omalley)
  10. HADOOP-3543. Update the copyright year to 2008.
      (cdouglas via omalley)
  11. HADOOP-3587. Add a unit test for the contrib/data_join framework.
      (cdouglas)
  12. HADOOP-3402. Add terasort example program
      (omalley)
  13. HADOOP-3660. Add replication factor for injecting blocks in simulated datanodes.
      (Sanjay Radia via cdouglas)
  14. HADOOP-3684. Add a cloning function to the contrib/data_join framework permitting users to define a more efficient method for cloning values from the reduce than serialization/deserialization.
      (Runping Qi via cdouglas)
  15. HADOOP-3478. Improves the handling of map output fetching. Now the randomization is by the hosts (and not the map outputs themselves).
      (Jothi Padmanabhan via ddas)
  16. HADOOP-3617. Removed redundant checks of accounting space in MapTask and makes the spill thread persistent so as to avoid creating a new one for each spill.
      (Chris Douglas via acmurthy)
  17. HADOOP-3412. Factor the scheduler out of the JobTracker and make it pluggable.
      (Tom White and Brice Arnould via omalley)
  18. HADOOP-3756. Minor. Remove unused dfs.client.buffer.dir from hadoop-default.xml.
      (rangadi)
  19. HADOOP-3747. Adds counter suport for MultipleOutputs.
      (Alejandro Abdelnur via ddas)
  20. HADOOP-3169. LeaseChecker daemon should not be started in DFSClient constructor. (TszWo (Nicholas), SZE via hairong)
  21. HADOOP-3824. Move base functionality of StatusHttpServer to a core package. (TszWo (Nicholas), SZE via cdouglas)
  22. HADOOP-3646. Add a bzip2 compatible codec, so bzip compressed data may be processed by map/reduce.
      (Abdul Qadeer via cdouglas)
  23. HADOOP-3861. MapFile.Reader and Writer should implement Closeable.
      (tomwhite via omalley)
  24. HADOOP-3791. Introduce generics into ReflectionUtils.
      (Chris Smith via cdouglas)
  25. HADOOP-3694. Improve unit test performance by changing MiniDFSCluster to listen only on 127.0.0.1.
      (cutting)
  26. HADOOP-3620. Namenode should synchronously resolve a datanode's network location when the datanode registers.
      (hairong)
  27. HADOOP-3860. NNThroughputBenchmark is extended with rename and delete benchmarks.
      (shv)
  28. HADOOP-3892. Include unix group name in JobConf.
      (Matei Zaharia via johan)
  29. HADOOP-3875. Change the time period between heartbeats to be relative to the end of the heartbeat rpc, rather than the start. This causes better behavior if the JobTracker is overloaded.
      (acmurthy via omalley)
  30. HADOOP-3853. Move multiple input format (HADOOP-372) extension to library package.
      (tomwhite via johan)
  31. HADOOP-9. Use roulette scheduling for temporary space when the size is not known.
      (Ari Rabkin via omalley)
  32. HADOOP-3202. Use recursive delete rather than FileUtil.fullyDelete.
      (Amareshwari Sriramadasu via omalley)
  33. HADOOP-3368. Remove common-logging.properties from conf.
      (Steve Loughran via omalley)
  34. HADOOP-3851. Fix spelling mistake in FSNamesystemMetrics.
      (Steve Loughran via omalley)
  35. HADOOP-3780. Remove asynchronous resolution of network topology in the JobTracker
      (Amar Kamat via omalley)
  36. HADOOP-3852. Add ShellCommandExecutor.toString method to make nicer error messages.
      (Steve Loughran via omalley)
  37. HADOOP-3844. Include message of local exception in RPC client failures.
      (Steve Loughran via omalley)
  38. HADOOP-3935. Split out inner classes from DataNode.java.
      (johan)
  39. HADOOP-3905. Create generic interfaces for edit log streams.
      (shv)
  40. HADOOP-3062. Add metrics to DataNode and TaskTracker to record network traffic for HDFS reads/writes and MR shuffling.
      (cdouglas)
  41. HADOOP-3742. Remove HDFS from public java doc and add javadoc-dev for generative javadoc for developers.
      (Sanjay Radia via omalley)
  42. HADOOP-3944. Improve documentation for public TupleWritable class in join package.
      (Chris Douglas via enis)
  43. HADOOP-2330. Preallocate HDFS transaction log to improve performance.
      (dhruba and hairong)
  44. HADOOP-3965. Convert DataBlockScanner into a package private class.
      (shv)
  45. HADOOP-3488. Prevent hadoop-daemon from rsync'ing log files
      (Stefan Groshupf and Craig Macdonald via omalley)
  46. HADOOP-3342. Change the kill task actions to require http post instead of get to prevent accidental crawls from triggering it.
      (enis via omalley)
  47. HADOOP-3937. Limit the job name in the job history filename to 50 characters.
      (Matei Zaharia via omalley)
  48. HADOOP-3943. Remove unnecessary synchronization in NetworkTopology.pseudoSortByDistance.
      (hairong via omalley)
  49. HADOOP-3498. File globbing alternation should be able to span path components.
      (tomwhite)
  50. HADOOP-3361. Implement renames for NativeS3FileSystem.
      (Albert Chern via tomwhite)
  51. HADOOP-3605. Make EC2 scripts show an error message if AWS_ACCOUNT_ID is unset.
      (Al Hoang via tomwhite)
  52. HADOOP-4147. Remove unused class JobWithTaskContext from class JobInProgress.
      (Amareshwari Sriramadasu via johan)
  53. HADOOP-4151. Add a byte-comparable interface that both Text and BytesWritable implement.
      (cdouglas via omalley)
  54. HADOOP-4174. Move fs image/edit log methods from ClientProtocol to NamenodeProtocol.
      (shv via szetszwo)
  55. HADOOP-4181. Include a .gitignore and saveVersion.sh change to support developing under git.
      (omalley)
  56. HADOOP-4186. Factor LineReader out of LineRecordReader.
      (tomwhite via omalley)
  57. HADOOP-4184. Break the module dependencies between core, hdfs, and mapred.
      (tomwhite via omalley)
  58. HADOOP-4075. test-patch.sh now spits out ant commands that it runs.
      (Ramya R via nigel)
  59. HADOOP-4117. Improve configurability of Hadoop EC2 instances.
      (tomwhite)
  60. HADOOP-2411. Add support for larger CPU EC2 instance types.
      (Chris K Wensel via tomwhite)
  61. HADOOP-4083. Changed the configuration attribute queue.name to mapred.job.queue.name.
      (Hemanth Yamijala via acmurthy)
  62. HADOOP-4194. Added the JobConf and JobID to job-related methods in JobTrackerInstrumentation for better metrics.
      (Mac Yang via acmurthy)
  63. HADOOP-3975. Change test-patch script to report working the dir modifications preventing the suite from being run.
      (Ramya R via cdouglas)
  64. HADOOP-4124. Added a command-line switch to allow users to set job priorities, also allow it to be manipulated via the web-ui.
      (Hemanth Yamijala via acmurthy)
  65. HADOOP-2165. Augmented JobHistory to include the URIs to the tasks' userlogs.
      (Vinod Kumar Vavilapalli via acmurthy)
  66. HADOOP-4062. Remove the synchronization on the output stream when a connection is closed and also remove an undesirable exception when a client is stoped while there is no pending RPC request.
      (hairong)
  67. HADOOP-4227. Remove the deprecated class org.apache.hadoop.fs.ShellCommand.
      (szetszwo)
  68. HADOOP-4006. Clean up FSConstants and move some of the constants to better places.
      (Sanjay Radia via rangadi)
  69. HADOOP-4279. Trace the seeds of random sequences in append unit tests to make itermitant failures reproducible.
      (szetszwo via cdouglas)
  70. HADOOP-4209. Remove the change to the format of task attempt id by incrementing the task attempt numbers by 1000 when the job restarts.
      (Amar Kamat via omalley)
  71. HADOOP-4301. Adds forrest doc for the skip bad records feature.
      (Sharad Agarwal via ddas)
  72. HADOOP-4354. Separate TestDatanodeDeath.testDatanodeDeath() into 4 tests.
      (szetszwo)
  73. HADOOP-3790. Add more unit tests for testing HDFS file append.
      (szetszwo)
  74. HADOOP-4321. Include documentation for the capacity scheduler.
      (Hemanth Yamijala via omalley)
  75. HADOOP-4424. Change menu layout for Hadoop documentation (Boris Shkolnik via cdouglas).
  76. HADOOP-4438. Update forrest documentation to include missing FsShell commands.
      (Suresh Srinivas via cdouglas)
  77. HADOOP-4105. Add forrest documentation for libhdfs.
      (Pete Wyckoff via cutting)
  78. HADOOP-4510. Make getTaskOutputPath public.
      (Chris Wensel via omalley)
- OPTIMIZATIONS (11)
  1. HADOOP-3556. Removed lock contention in MD5Hash by changing the singleton MessageDigester by an instance per Thread using ThreadLocal.
     (Iv?n de Prado via omalley)
  2. HADOOP-3328. When client is writing data to DFS, only the last datanode in the pipeline needs to verify the checksum. Saves around 30% CPU on intermediate datanodes.
     (rangadi)
  3. HADOOP-3863. Use a thread-local string encoder rather than a static one that is protected by a lock.
     (acmurthy via omalley)
  4. HADOOP-3864. Prevent the JobTracker from locking up when a job is being initialized.
     (acmurthy via omalley)
  5. HADOOP-3816. Faster directory listing in KFS.
     (Sriram Rao via omalley)
  6. HADOOP-2130. Pipes submit job should have both blocking and non-blocking versions.
     (acmurthy via omalley)
  7. HADOOP-3769. Make the SampleMapper and SampleReducer from GenericMRLoadGenerator public, so they can be used in other contexts.
     (Lingyun Yang via omalley)
  8. HADOOP-3514. Inline the CRCs in intermediate files as opposed to reading it from a different .crc file.
     (Jothi Padmanabhan via ddas)
  9. HADOOP-3638. Caches the iFile index files in memory to reduce seeks
     (Jothi Padmanabhan via ddas)
  10. HADOOP-4225. FSEditLog.logOpenFile() should persist accessTime rather than modificationTime.
      (shv)
  11. HADOOP-4380. Made several new classes (Child, JVMId, JobTrackerInstrumentation, QueueManager, ResourceEstimator, TaskTrackerInstrumentation, and TaskTrackerMetricsInst) in org.apache.hadoop.mapred package private instead of public.
      (omalley)
- BUG FIXES (152)
  1. HADOOP-3563. Refactor the distributed upgrade code so that it is easier to identify datanode and namenode related code.
     (dhruba)
  2. HADOOP-3640. Fix the read method in the NativeS3InputStream.
     (tomwhite via omalley)
  3. HADOOP-3711. Fixes the Streaming input parsing to properly find the separator.
     (Amareshwari Sriramadasu via ddas)
  4. HADOOP-3725. Prevent TestMiniMRMapDebugScript from swallowing exceptions.
     (Steve Loughran via cdouglas)
  5. HADOOP-3726. Throw exceptions from TestCLI setup and teardown instead of swallowing them.
     (Steve Loughran via cdouglas)
  6. HADOOP-3721. Refactor CompositeRecordReader and related mapred.join classes to make them clearer.
     (cdouglas)
  7. HADOOP-3720. Re-read the config file when dfsadmin -refreshNodes is invoked so dfs.hosts and dfs.hosts.exclude are observed.
     (lohit vijayarenu via cdouglas)
  8. HADOOP-3485. Allow writing to files over fuse.
     (Pete Wyckoff via dhruba)
  9. HADOOP-3723. The flags to the libhdfs.create call can be treated as a bitmask.
     (Pete Wyckoff via dhruba)
  10. HADOOP-3643. Filter out completed tasks when asking for running tasks in the JobTracker web/ui.
      (Amar Kamat via omalley)
  11. HADOOP-3777. Ensure that Lzo compressors/decompressors correctly handle the case where native libraries aren't available.
      (Chris Douglas via acmurthy)
  12. HADOOP-3728. Fix SleepJob so that it doesn't depend on temporary files, this ensures we can now run more than one instance of SleepJob simultaneously.
      (Chris Douglas via acmurthy)
  13. HADOOP-3795. Fix saving image files on Namenode with different checkpoint stamps.
      (Lohit Vijayarenu via mahadev)
  14. HADOOP-3624. Improving createeditslog to create tree directory structure.
      (Lohit Vijayarenu via mahadev)
  15. HADOOP-3778. DFSInputStream.seek() did not retry in case of some errors.
      (LN via rangadi)
  16. HADOOP-3661. The handling of moving files deleted through fuse-dfs to Trash made similar to the behaviour from dfs shell.
      (Pete Wyckoff via dhruba)
  17. HADOOP-3819. Unset LANG and LC_CTYPE in saveVersion.sh to make it compatible with non-English locales.
      (Rong-En Fan via cdouglas)
  18. HADOOP-3848. Cache calls to getSystemDir in the TaskTracker instead of calling it for each task start.
      (acmurthy via omalley)
  19. HADOOP-3131. Fix reduce progress reporting for compressed intermediate data.
      (Matei Zaharia via acmurthy)
  20. HADOOP-3796. fuse-dfs configuration is implemented as file system mount options.
      (Pete Wyckoff via dhruba)
  21. HADOOP-3836. Fix TestMultipleOutputs to correctly clean up.
      (Alejandro Abdelnur via acmurthy)
  22. HADOOP-3805. Improve fuse-dfs write performance.
      (Pete Wyckoff via zshao)
  23. HADOOP-3846. Fix unit test CreateEditsLog to generate paths correctly.
      (Lohit Vjayarenu via cdouglas)
  24. HADOOP-3904. Fix unit tests using the old dfs package name. (TszWo (Nicholas), SZE via johan)
  25. HADOOP-3319. Fix some HOD error messages to go stderr instead of stdout.
      (Vinod Kumar Vavilapalli via omalley)
  26. HADOOP-3907. Move INodeDirectoryWithQuota to its own .java file. (Tsz Wo (Nicholas), SZE via hairong)
  27. HADOOP-3919. Fix attribute name in hadoop-default for mapred.jobtracker.instrumentation.
      (Ari Rabkin via omalley)
  28. HADOOP-3903. Change the package name for the servlets to be hdfs instead of dfs. (Tsz Wo (Nicholas) Sze via omalley)
  29. HADOOP-3773. Change Pipes to set the default map output key and value types correctly.
      (Koji Noguchi via omalley)
  30. HADOOP-3952. Fix compilation error in TestDataJoin referencing dfs package.
      (omalley)
  31. HADOOP-3951. Fix package name for FSNamesystem logs and modify other hard-coded Logs to use the class name.
      (cdouglas)
  32. HADOOP-3889. Improve error reporting from HftpFileSystem, handling in DistCp. (Tsz Wo (Nicholas), SZE via cdouglas)
  33. HADOOP-3946. Fix TestMapRed after hadoop-3664.
      (tomwhite via omalley)
  34. HADOOP-3949. Remove duplicate jars from Chukwa.
      (Jerome Boulon via omalley)
  35. HADOOP-3933. DataNode sometimes sends up to io.byte.per.checksum bytes more than required to client.
      (Ning Li via rangadi)
  36. HADOOP-3962. Shell command "fs -count" should support paths with different file systems. (Tsz Wo (Nicholas), SZE via mahadev)
  37. HADOOP-3957. Fix javac warnings in DistCp and TestCopyFiles. (Tsz Wo (Nicholas), SZE via cdouglas)
  38. HADOOP-3958. Fix TestMapRed to check the success of test-job.
      (omalley via acmurthy)
  39. HADOOP-3985. Fix TestHDFSServerPorts to use random ports.
      (Hairong Kuang via omalley)
  40. HADOOP-3964. Fix javadoc warnings introduced by FailMon.
      (dhruba)
  41. HADOOP-3785. Fix FileSystem cache to be case-insensitive for scheme and authority.
      (Bill de hOra via cdouglas)
  42. HADOOP-3506. Fix a rare NPE caused by error handling in S3.
      (Tom White via cdouglas)
  43. HADOOP-3705. Fix mapred.join parser to accept InputFormats named with underscore and static, inner classes.
      (cdouglas)
  44. HADOOP-4023. Fix javadoc warnings introduced when the HDFS javadoc was made private.
      (omalley)
  45. HADOOP-4030. Remove lzop from the default list of codecs.
      (Arun Murthy via cdouglas)
  46. HADOOP-3961. Fix task disk space requirement estimates for virtual input jobs. Delays limiting task placement until after 10% of the maps have finished.
      (Ari Rabkin via omalley)
  47. HADOOP-2168. Fix problem with C++ record reader's progress not being reported to framework.
      (acmurthy via omalley)
  48. HADOOP-3966. Copy findbugs generated output files to PATCH_DIR while running test-patch.
      (Ramya R via lohit)
  49. HADOOP-4037. Fix the eclipse plugin for versions of kfs and log4j.
      (nigel via omalley)
  50. HADOOP-3950. Cause the Mini MR cluster to wait for task trackers to register before continuing.
      (enis via omalley)
  51. HADOOP-3910. Remove unused ClusterTestDFSNamespaceLogging and ClusterTestDFS. (Tsz Wo (Nicholas), SZE via cdouglas)
  52. HADOOP-3954. Disable record skipping by default.
      (Sharad Agarwal via cdouglas)
  53. HADOOP-4050. Fix TestFairScheduler to use absolute paths for the work directory.
      (Matei Zaharia via omalley)
  54. HADOOP-4069. Keep temporary test files from TestKosmosFileSystem under test.build.data instead of /tmp.
      (lohit via omalley)
  55. HADOOP-4078. Create test files for TestKosmosFileSystem in separate directory under test.build.data.
      (lohit)
  56. HADOOP-3968. Fix getFileBlockLocations calls to use FileStatus instead of Path reflecting the new API.
      (Pete Wyckoff via lohit)
  57. HADOOP-3963. libhdfs does not exit on its own, instead it returns error to the caller and behaves as a true library.
      (Pete Wyckoff via dhruba)
  58. HADOOP-4100. Removes the cleanupTask scheduling from the Scheduler implementations and moves it to the JobTracker.
      (Amareshwari Sriramadasu via ddas)
  59. HADOOP-4097. Make hive work well with speculative execution turned on.
      (Joydeep Sen Sarma via dhruba)
  60. HADOOP-4113. Changes to libhdfs to not exit on its own, rather return an error code to the caller.
      (Pete Wyckoff via dhruba)
  61. HADOOP-4054. Remove duplicate lease removal during edit log loading.
      (hairong)
  62. HADOOP-4071. FSNameSystem.isReplicationInProgress should add an underReplicated block to the neededReplication queue using method "add" not "update".
      (hairong)
  63. HADOOP-4154. Fix type warnings in WritableUtils.
      (szetszwo via omalley)
  64. HADOOP-4133. Log files generated by Hive should reside in the build directory.
      (Prasad Chakka via dhruba)
  65. HADOOP-4094. Hive now has hive-default.xml and hive-site.xml similar to core hadoop.
      (Prasad Chakka via dhruba)
  66. HADOOP-4112. Handles cleanupTask in JobHistory
      (Amareshwari Sriramadasu via ddas)
  67. HADOOP-3831. Very slow reading clients sometimes failed while reading.
      (rangadi)
  68. HADOOP-4155. Use JobTracker's start time while initializing JobHistory's JobTracker Unique String.
      (lohit)
  69. HADOOP-4099. Fix null pointer when using HFTP from an 0.18 server.
      (dhruba via omalley)
  70. HADOOP-3570. Includes user specified libjar files in the client side classpath path.
      (Sharad Agarwal via ddas)
  71. HADOOP-4129. Changed memory limits of TaskTracker and Tasks to be in KiloBytes rather than bytes.
      (Vinod Kumar Vavilapalli via acmurthy)
  72. HADOOP-4139. Optimize Hive multi group-by.
      (Namin Jain via dhruba)
  73. HADOOP-3911. Add a check to fsck options to make sure -files is not the first option to resolve conflicts with GenericOptionsParser
      (lohit)
  74. HADOOP-3623. Refactor LeaseManager.
      (szetszwo)
  75. HADOOP-4125. Handles Reduce cleanup tip on the web ui.
      (Amareshwari Sriramadasu via ddas)
  76. HADOOP-4087. Hive Metastore API for php and python clients.
      (Prasad Chakka via dhruba)
  77. HADOOP-4197. Update DATA_TRANSFER_VERSION for HADOOP-3981.
      (szetszwo)
  78. HADOOP-4138. Refactor the Hive SerDe library to better structure the interfaces to the serializer and de-serializer.
      (Zheng Shao via dhruba)
  79. HADOOP-4195. Close compressor before returning to codec pool.
      (acmurthy via omalley)
  80. HADOOP-2403. Escapes some special characters before logging to history files.
      (Amareshwari Sriramadasu via ddas)
  81. HADOOP-4200. Fix a bug in the test-patch.sh script.
      (Ramya R via nigel)
  82. HADOOP-4084. Add explain plan capabilities to Hive Query Language.
      (Ashish Thusoo via dhruba)
  83. HADOOP-4121. Preserve cause for exception if the initialization of HistoryViewer for JobHistory fails.
      (Amareshwari Sri Ramadasu via acmurthy)
  84. HADOOP-4213. Fixes NPE in TestLimitTasksPerJobTaskScheduler.
      (Sreekanth Ramakrishnan via ddas)
  85. HADOOP-4077. Setting access and modification time for a file requires write permissions on the file.
      (dhruba)
  86. HADOOP-3592. Fix a couple of possible file leaks in FileUtil
      (Bill de hOra via rangadi)
  87. HADOOP-4120. Hive interactive shell records the time taken by a query.
      (Raghotham Murthy via dhruba)
  88. HADOOP-4090. The hive scripts pick up hadoop from HADOOP_HOME and then the path.
      (Raghotham Murthy via dhruba)
  89. HADOOP-4242. Remove extra ";" in FSDirectory that blocks compilation in some IDE's.
      (szetszwo via omalley)
  90. HADOOP-4249. Fix eclipse path to include the hsqldb.jar.
      (szetszwo via omalley)
  91. HADOOP-4247. Move InputSampler into org.apache.hadoop.mapred.lib, so that examples.jar doesn't depend on tools.jar.
      (omalley)
  92. HADOOP-4269. Fix the deprecation of LineReader by extending the new class into the old name and deprecating it. Also update the tests to test the new class.
      (cdouglas via omalley)
  93. HADOOP-4280. Fix conversions between seconds in C and milliseconds in Java for access times for files.
      (Pete Wyckoff via rangadi)
  94. HADOOP-4254. -setSpaceQuota command does not convert "TB" extenstion to terabytes properly. Implementation now uses StringUtils for parsing this.
      (Raghu Angadi)
  95. HADOOP-4259. Findbugs should run over tools.jar also.
      (cdouglas via omalley)
  96. HADOOP-4275. Move public method isJobValidName from JobID to a private method in JobTracker.
      (omalley)
  97. HADOOP-4173. fix failures in TestProcfsBasedProcessTree and TestTaskTrackerMemoryManager tests. ProcfsBasedProcessTree and memory management in TaskTracker are disabled on Windows.
      (Vinod K V via rangadi)
  98. HADOOP-4189. Fixes the history blocksize & intertracker protocol version issues introduced as part of HADOOP-3245.
      (Amar Kamat via ddas)
  99. HADOOP-4190. Fixes the backward compatibility issue with Job History. introduced by HADOOP-3245 and HADOOP-2403.
      (Amar Kamat via ddas)
  100. HADOOP-4237. Fixes the TestStreamingBadRecords.testNarrowDown testcase.
       (Sharad Agarwal via ddas)
  101. HADOOP-4274. Capacity scheduler accidently modifies the underlying data structures when browing the job lists.
       (Hemanth Yamijala via omalley)
  102. HADOOP-4309. Fix eclipse-plugin compilation.
       (cdouglas)
  103. HADOOP-4232. Fix race condition in JVM reuse when multiple slots become free.
       (ddas via acmurthy)
  104. HADOOP-4302. Fix a race condition in TestReduceFetch that can yield false negatvies.
       (cdouglas)
  105. HADOOP-3942. Update distcp documentation to include features introduced in HADOOP-3873, HADOOP-3939. (Tsz Wo (Nicholas), SZE via cdouglas)
  106. HADOOP-4319. fuse-dfs dfs_read function returns as many bytes as it is told to read unlesss end-of-file is reached.
       (Pete Wyckoff via dhruba)
  107. HADOOP-4246. Ensure we have the correct lower bound on the number of retries for fetching map-outputs; also fixed the case where the reducer automatically kills on too many unique map-outputs could not be fetched for small jobs.
       (Amareshwari Sri Ramadasu via acmurthy)
  108. HADOOP-4163. Report FSErrors from map output fetch threads instead of merely logging them.
       (Sharad Agarwal via cdouglas)
  109. HADOOP-4261. Adds a setup task for jobs. This is required so that we don't setup jobs that haven't been inited yet (since init could lead to job failure). Only after the init has successfully happened do we launch the setupJob task.
       (Amareshwari Sriramadasu via ddas)
  110. HADOOP-4256. Removes Completed and Failed Job tables from jobqueue_details.jsp.
       (Sreekanth Ramakrishnan via ddas)
  111. HADOOP-4267. Occasional exceptions during shutting down HSQLDB is logged but not rethrown.
       (enis)
  112. HADOOP-4018. The number of tasks for a single job cannot exceed a pre-configured maximum value.
       (dhruba)
  113. HADOOP-4288. Fixes a NPE problem in CapacityScheduler.
       (Amar Kamat via ddas)
  114. HADOOP-4014. Create hard links with 'fsutil hardlink' on Windows.
       (shv)
  115. HADOOP-4393. Merged org.apache.hadoop.fs.permission.AccessControlException and org.apache.hadoop.security.AccessControlIOException into a single class hadoop.security.AccessControlException.
       (omalley via acmurthy)
  116. HADOOP-4287. Fixes an issue to do with maintaining counts of running/pending maps/reduces.
       (Sreekanth Ramakrishnan via ddas)
  117. HADOOP-4361. Makes sure that jobs killed from command line are killed fast (i.e., there is a slot to run the cleanup task soon).
       (Amareshwari Sriramadasu via ddas)
  118. HADOOP-4400. Add "hdfs://" to fs.default.name on quickstart.html.
       (Jeff Hammerbacher via omalley)
  119. HADOOP-4378. Fix TestJobQueueInformation to use SleepJob rather than WordCount via TestMiniMRWithDFS.
       (Sreekanth Ramakrishnan via acmurthy)
  120. HADOOP-4376. Fix formatting in hadoop-default.xml for hadoop.http.filter.initializers.
       (Enis Soztutar via acmurthy)
  121. HADOOP-4410. Adds an extra arg to the API FileUtil.makeShellPath to determine whether to canonicalize file paths or not.
       (Amareshwari Sriramadasu via ddas)
  122. HADOOP-4236. Ensure un-initialized jobs are killed correctly on user-demand.
       (Sharad Agarwal via acmurthy)
  123. HADOOP-4373. Fix calculation of Guaranteed Capacity for the capacity-scheduler.
       (Hemanth Yamijala via acmurthy)
  124. HADOOP-4053. Schedulers must be notified when jobs complete.
       (Amar Kamat via omalley)
  125. HADOOP-4335. Fix FsShell -ls for filesystems without owners/groups.
       (David Phillips via cdouglas)
  126. HADOOP-4426. TestCapacityScheduler broke due to the two commits HADOOP-4053 and HADOOP-4373. This patch fixes that.
       (Hemanth Yamijala via ddas)
  127. HADOOP-4418. Updates documentation in forrest for Mapred, streaming and pipes.
       (Amareshwari Sriramadasu via ddas)
  128. HADOOP-3155. Ensure that there is only one thread fetching TaskCompletionEvents on TaskTracker re-init.
       (Dhruba Borthakur via acmurthy)
  129. HADOOP-4425. Fix EditLogInputStream to overload the bulk read method.
       (cdouglas)
  130. HADOOP-4427. Adds the new queue/job commands to the manual.
       (Sreekanth Ramakrishnan via ddas)
  131. HADOOP-4278. Increase debug logging for unit test TestDatanodeDeath. Fix the case when primary is dead.
       (dhruba via szetszwo)
  132. HADOOP-4423. Keep block length when the block recovery is triggered by append.
       (szetszwo)
  133. HADOOP-4449. Fix dfsadmin usage.
       (Raghu Angadi via cdouglas)
  134. HADOOP-4455. Added TestSerDe so that unit tests can run successfully.
       (Ashish Thusoo via dhruba)
  135. HADOOP-4457. Fixes an input split logging problem introduced by HADOOP-3245.
       (Amareshwari Sriramadasu via ddas)
  136. HADOOP-4464. Separate out TestFileCreationClient from TestFileCreation. (Tsz Wo (Nicholas), SZE via cdouglas)
  137. HADOOP-4404. saveFSImage() removes files from a storage directory that do not correspond to its type.
       (shv)
  138. HADOOP-4149. Fix handling of updates to the job priority, by changing the list of jobs to be keyed by the priority, submit time, and job tracker id.
       (Amar Kamat via omalley)
  139. HADOOP-4296. Fix job client failures by not retiring a job as soon as it is finished.
       (dhruba)
  140. HADOOP-4439. Remove configuration variables that aren't usable yet, in particular mapred.tasktracker.tasks.maxmemory and mapred.task.max.memory.
       (Hemanth Yamijala via omalley)
  141. HADOOP-4230. Fix for serde2 interface, limit operator, select * operator, UDF trim functions and sampling.
       (Ashish Thusoo via dhruba)
  142. HADOOP-4358. No need to truncate access time in INode. Also fixes NPE in CreateEditsLog.
       (Raghu Angadi)
  143. HADOOP-4387. TestHDFSFileSystemContract fails on windows nightly builds.
       (Raghu Angadi)
  144. HADOOP-4466. Ensure that SequenceFileOutputFormat isn't tied to Writables and can be used with other Serialization frameworks.
       (Chris Wensel via acmurthy)
  145. HADOOP-4525. Fix ipc.server.ipcnodelay originally missed in in HADOOP-2232.
       (cdouglas via Clint Morgan)
  146. HADOOP-4498. Ensure that JobHistory correctly escapes the job name so that regex patterns work.
       (Chris Wensel via acmurthy)
  147. HADOOP-4446. Modify guaranteed capacity labels in capacity scheduler's UI to reflect the information being displayed.
       (Sreekanth Ramakrishnan via yhemanth)
  148. HADOOP-4282. Some user facing URLs are not filtered by user filters.
       (szetszwo)
  149. HADOOP-4595. Fixes two race conditions - one to do with updating free slot count, and another to do with starting the MapEventsFetcher thread.
       (ddas)
  150. HADOOP-4552. Fix a deadlock in RPC server.
       (Raghu Angadi)
  151. HADOOP-4471. Sort running jobs by priority in the capacity scheduler.
       (Amar Kamat via yhemanth)
  152. HADOOP-4500. Fix MultiFileSplit to get the FileSystem from the relevant path rather than the JobClient.
       (Joydeep Sen Sarma via cdouglas)

### Release 0.18.4 - Unreleased

- BUG FIXES (8)
  1. HADOOP-5114. Remove timeout for accept() in DataNode. This makes accept() fail in JDK on Windows and causes many tests to fail.
     (Raghu Angadi)
  2. HADOOP-5192. Block receiver should not remove a block that's created or being written by other threads.
     (hairong)
  3. HADOOP-5134. FSNamesystem#commitBlockSynchronization adds under-construction block locations to blocksMap.
     (Dhruba Borthakur via hairong)
  4. HADOOP-5412. Simulated DataNode should not write to a block that's being written by another thread.
     (hairong)
  5. HADOOP-5465. Fix the problem of blocks remaining under-replicated by providing synchronized modification to the counter xmitsInProgress in DataNode.
     (hairong)
  6. HADOOP-5557. Fixes some minor problems in TestOverReplicatedBlocks.
     (szetszwo)
  7. HADOOP-5644. Namenode is stuck in safe mode.
     (suresh Srinivas via hairong)
  8. HADOOP-6017. Lease Manager in NameNode does not handle certain characters in filenames. This results in fatal errors in Secondary NameNode and while restrating NameNode. (Tsz Wo (Nicholas), SZE via rangadi)

### Release 0.18.3 - 2009-01-27

- IMPROVEMENTS (2)
  1. HADOOP-4150. Include librecordio in hadoop releases.
     (Giridharan Kesavan via acmurthy)
  2. HADOOP-4668. Improve documentation for setCombinerClass to clarify the restrictions on combiners.
     (omalley)
- BUG FIXES (40)
  1. HADOOP-4499. DFSClient should invoke checksumOk only once.
     (Raghu Angadi)
  2. HADOOP-4597. Calculate mis-replicated blocks when safe-mode is turned off manually.
     (shv)
  3. HADOOP-3121. lsr should keep listing the remaining items but not terminate if there is any IOException.
     (szetszwo)
  4. HADOOP-4610. Always calculate mis-replicated blocks when safe-mode is turned off.
     (shv)
  5. HADOOP-3883. Limit namenode to assign at most one generation stamp for a particular block within a short period.
     (szetszwo)
  6. HADOOP-4556. Block went missing.
     (hairong)
  7. HADOOP-4643. NameNode should exclude excessive replicas when counting live replicas for a block.
     (hairong)
  8. HADOOP-4703. Should not wait for proxy forever in lease recovering.
     (szetszwo)
  9. HADOOP-4647. NamenodeFsck should close the DFSClient it has created.
     (szetszwo)
  10. HADOOP-4616. Fuse-dfs can handle bad values from FileSystem.read call.
      (Pete Wyckoff via dhruba)
  11. HADOOP-4061. Throttle Datanode decommission monitoring in Namenode.
      (szetszwo)
  12. HADOOP-4659. Root cause of connection failure is being lost to code that uses it for delaying startup.
      (Steve Loughran and Hairong via hairong)
  13. HADOOP-4614. Lazily open segments when merging map spills to avoid using too many file descriptors.
      (Yuri Pradkin via cdouglas)
  14. HADOOP-4257. The DFS client should pick only one datanode as the candidate to initiate lease recovery. (Tsz Wo (Nicholas), SZE via dhruba)
  15. HADOOP-4713. Fix librecordio to handle records larger than 64k.
      (Christian Kunz via cdouglas)
  16. HADOOP-4635. Fix a memory leak in fuse dfs.
      (pete wyckoff via mahadev)
  17. HADOOP-4714. Report status between merges and make the number of records between progress reports configurable.
      (Jothi Padmanabhan via cdouglas)
  18. HADOOP-4726. Fix documentation typos "the the".
      (Edward J. Yoon via szetszwo)
  19. HADOOP-4679. Datanode prints tons of log messages: waiting for threadgroup to exit, active threads is XX.
      (hairong)
  20. HADOOP-4746. Job output directory should be normalized.
      (hairong)
  21. HADOOP-4717. Removal of default port# in NameNode.getUri() causes a map/reduce job failed to prompt temporary output.
      (hairong)
  22. HADOOP-4778. Check for zero size block meta file when updating a block.
      (szetszwo)
  23. HADOOP-4742. Replica gets deleted by mistake.
      (Wang Xu via hairong)
  24. HADOOP-4702. Failed block replication leaves an incomplete block in receiver's tmp data directory.
      (hairong)
  25. HADOOP-4613. Fix block browsing on Web UI.
      (Johan Oskarsson via shv)
  26. HADOOP-4806. HDFS rename should not use src path as a regular expression.
      (szetszwo)
  27. HADOOP-4795. Prevent lease monitor getting into an infinite loop when leases and the namespace tree does not match.
      (szetszwo)
  28. HADOOP-4620. Fixes Streaming to handle well the cases of map/reduce with empty input/output.
      (Ravi Gummadi via ddas)
  29. HADOOP-4857. Fixes TestUlimit to have exactly 1 map in the jobs spawned.
      (Ravi Gummadi via ddas)
  30. HADOOP-4810. Data lost at cluster startup time.
      (hairong)
  31. HADOOP-4797. Improve how RPC server reads and writes large buffers. Avoids soft-leak of direct buffers and excess copies in NIO layer.
      (Raghu Angadi)
  32. HADOOP-4840. TestNodeCount sometimes fails with NullPointerException.
      (hairong)
  33. HADOOP-4904. Fix deadlock while leaving safe mode.
      (shv)
  34. HADOOP-1980. 'dfsadmin -safemode enter' should prevent the namenode from leaving safemode automatically.
      (shv)
  35. HADOOP-4951. Lease monitor should acquire the LeaseManager lock but not the Monitor lock.
      (szetszwo)
  36. HADOOP-4935. processMisReplicatedBlocks() should not clear excessReplicateMap.
      (shv)
  37. HADOOP-4961. Fix ConcurrentModificationException in lease recovery of empty files.
      (shv)
  38. HADOOP-4971. A long (unexpected) delay at datanodes could make subsequent block reports from many datanode at the same time.
      (Raghu Angadi)
  39. HADOOP-4910. NameNode should exclude replicas when choosing excessive replicas to delete to avoid data lose.
      (hairong)
  40. HADOOP-4983. Fixes a problem in updating Counters in the status reporting.
      (Amareshwari Sriramadasu via ddas)

### Release 0.18.2 - 2008-11-03

- BUG FIXES (16)
  1. HADOOP-3614. Fix a bug that Datanode may use an old GenerationStamp to get meta file.
     (szetszwo)
  2. HADOOP-4314. Simulated datanodes should not include blocks that are still being written in their block report.
     (Raghu Angadi)
  3. HADOOP-4228. dfs datanode metrics, bytes_read and bytes_written, overflow due to incorrect type used.
     (hairong)
  4. HADOOP-4395. The FSEditLog loading is incorrect for the case OP_SET_OWNER.
     (szetszwo)
  5. HADOOP-4351. FSNamesystem.getBlockLocationsInternal throws ArrayIndexOutOfBoundsException.
     (hairong)
  6. HADOOP-4403. Make TestLeaseRecovery and TestFileCreation more robust.
     (szetszwo)
  7. HADOOP-4292. Do not support append() for LocalFileSystem.
     (hairong)
  8. HADOOP-4399. Make fuse-dfs multi-thread access safe.
     (Pete Wyckoff via dhruba)
  9. HADOOP-4369. Use setMetric(...) instead of incrMetric(...) for metrics averages.
     (Brian Bockelman via szetszwo)
  10. HADOOP-4469. Rename and add the ant task jar file to the tar file.
      (nigel)
  11. HADOOP-3914. DFSClient sends Checksum Ok only once for a block.
      (Christian Kunz via hairong)
  12. HADOOP-4467. SerializationFactory now uses the current context ClassLoader allowing for user supplied Serialization instances.
      (Chris Wensel via acmurthy)
  13. HADOOP-4517. Release FSDataset lock before joining ongoing create threads.
      (szetszwo)
  14. HADOOP-4526. fsck failing with NullPointerException.
      (hairong)
  15. HADOOP-4483 Honor the max parameter in DatanodeDescriptor.getBlockArray(..)
      (Ahad Rana and Hairong Kuang via szetszwo)
  16. HADOOP-4340. Correctly set the exit code from JobShell.main so that the 'hadoop jar' command returns the right code to the user.
      (acmurthy)
- NEW FEATURES (1)
  1. HADOOP-2421. Add jdiff output to documentation, listing all API changes from the prior release.
     (cutting)

### Release 0.18.1 - 2008-09-17

- IMPROVEMENTS (1)
  1. HADOOP-3934. Upgrade log4j to 1.2.15.
     (omalley)
- BUG FIXES (5)
  1. HADOOP-3995. In case of quota failure on HDFS, rename does not restore source filename.
     (rangadi)
  2. HADOOP-3821. Prevent SequenceFile and IFile from duplicating codecs in CodecPool when closed more than once.
     (Arun Murthy via cdouglas)
  3. HADOOP-4040. Remove coded default of the IPC idle connection timeout from the TaskTracker, which was causing HDFS client connections to not be collected.
     (ddas via omalley)
  4. HADOOP-4046. Made WritableComparable's constructor protected instead of private to re-enable class derivation.
     (cdouglas via omalley)
  5. HADOOP-3940. Fix in-memory merge condition to wait when there are no map outputs or when the final map outputs are being fetched without contention.
     (cdouglas)

### Release 0.18.0 - 2008-08-19

- INCOMPATIBLE CHANGES (23)
  1. HADOOP-2703. The default options to fsck skips checking files that are being written to. The output of fsck is incompatible with previous release.
     (lohit vijayarenu via dhruba)
  2. HADOOP-2865. FsShell.ls() printout format changed to print file names in the end of the line.
     (Edward J. Yoon via shv)
  3. HADOOP-3283. The Datanode has a RPC server. It currently supports two RPCs: the first RPC retrives the metadata about a block and the second RPC sets the generation stamp of an existing block. (Tsz Wo (Nicholas), SZE via dhruba)
  4. HADOOP-2797. Code related to upgrading to 0.14 (Block CRCs) is removed. As result, upgrade to 0.18 or later from 0.13 or earlier is not supported. If upgrading from 0.13 or earlier is required, please upgrade to an intermediate version (0.14-0.17) and then to this version.
     (rangadi)
  5. HADOOP-544. This issue introduces new classes JobID, TaskID and TaskAttemptID, which should be used instead of their string counterparts. Functions in JobClient, TaskReport, RunningJob, jobcontrol.Job and TaskCompletionEvent that use string arguments are deprecated in favor of the corresponding ones that use ID objects. Applications can use xxxID.toString() and xxxID.forName() methods to convert/restore objects to/from strings.
     (Enis Soztutar via ddas)
  6. HADOOP-2188. RPC client sends a ping rather than throw timeouts. RPC server does not throw away old RPCs. If clients and the server are on different versions, they are not able to function well. In addition, The property ipc.client.timeout is removed from the default hadoop configuration. It also removes metrics RpcOpsDiscardedOPsNum.
     (hairong)
  7. HADOOP-2181. This issue adds logging for input splits in Jobtracker log and jobHistory log. Also adds web UI for viewing input splits in job UI and history UI.
     (Amareshwari Sriramadasu via ddas)
  8. HADOOP-3226. Run combiners multiple times over map outputs as they are merged in both the map and the reduce tasks.
     (cdouglas via omalley)
  9. HADOOP-3329. DatanodeDescriptor objects should not be stored in the fsimage.
     (dhruba)
  10. HADOOP-2656. The Block object has a generation stamp inside it. Existing blocks get a generation stamp of 0. This is needed to support appends.
      (dhruba)
  11. HADOOP-3390. Removed deprecated ClientProtocol.abandonFileInProgress(). (Tsz Wo (Nicholas), SZE via rangadi)
  12. HADOOP-3405. Made some map/reduce internal classes non-public: MapTaskStatus, ReduceTaskStatus, JobSubmissionProtocol, CompletedJobStatusStore.
      (enis via omaley)
  13. HADOOP-3265. Removed depcrecated API getFileCacheHints().
      (Lohit Vijayarenu via rangadi)
  14. HADOOP-3310. The namenode instructs the primary datanode to do lease recovery. The block gets a new generation stamp. (Tsz Wo (Nicholas), SZE via dhruba)
  15. HADOOP-2909. Improve IPC idle connection management. Property ipc.client.maxidletime is removed from the default configuration, instead it is defined as twice of the ipc.client.connection.maxidletime. A connection with outstanding requests won't be treated as idle.
      (hairong)
  16. HADOOP-3459. Change in the output format of dfs -ls to more closely match /bin/ls. New format is: perm repl owner group size date name
      (Mukund Madhugiri via omally)
  17. HADOOP-3113. An fsync invoked on a HDFS file really really persists data! The datanode moves blocks in the tmp directory to the real block directory on a datanode-restart.
      (dhruba)
  18. HADOOP-3452. Change fsck to return non-zero status for a corrupt FileSystem.
      (lohit vijayarenu via cdouglas)
  19. HADOOP-3193. Include the address of the client that found the corrupted block in the log. Also include a CorruptedBlocks metric to track the size of the corrupted block map.
      (cdouglas)
  20. HADOOP-3512. Separate out the tools into a tools jar.
      (omalley)
  21. HADOOP-3598. Ensure that temporary task-output directories are not created if they are not necessary e.g. for Maps with no side-effect files.
      (acmurthy)
  22. HADOOP-3665. Modify WritableComparator so that it only creates instances of the keytype if the type does not define a WritableComparator. Calling the superclass compare will throw a NullPointerException. Also define a RawComparator for NullWritable and permit it to be written as a key to SequenceFiles.
      (cdouglas)
  23. HADOOP-3673. Avoid deadlock caused by DataNode RPC receoverBlock(). (Tsz Wo (Nicholas), SZE via rangadi)
- NEW FEATURES (25)
  1. HADOOP-3074. Provides a UrlStreamHandler for DFS and other FS, relying on FileSystem
     (taton)
  2. HADOOP-2585. Name-node imports namespace data from a recent checkpoint accessible via a NFS mount.
     (shv)
  3. HADOOP-3061. Writable types for doubles and bytes.
     (Andrzej Bialecki via omalley)
  4. HADOOP-2857. Allow libhdfs to set jvm options.
     (Craig Macdonald via omalley)
  5. HADOOP-3317. Add default port for HDFS namenode. The port in "hdfs:" URIs now defaults to 8020, so that one may simply use URIs of the form "hdfs://example.com/dir/file".
     (cutting)
  6. HADOOP-2019. Adds support for .tar, .tgz and .tar.gz files in DistributedCache
     (Amareshwari Sriramadasu via ddas)
  7. HADOOP-3058. Add FSNamesystem status metrics.
     (Lohit Vjayarenu via rangadi)
  8. HADOOP-1915. Allow users to specify counters via strings instead of enumerations.
     (tomwhite via omalley)
  9. HADOOP-2065. Delay invalidating corrupt replicas of block until its is removed from under replicated state. If all replicas are found to be corrupt, retain all copies and mark the block as corrupt.
     (Lohit Vjayarenu via rangadi)
  10. HADOOP-3221. Adds org.apache.hadoop.mapred.lib.NLineInputFormat, which splits files into splits each of N lines. N can be specified by configuration property "mapred.line.input.format.linespermap", which defaults to 1.
      (Amareshwari Sriramadasu via ddas)
  11. HADOOP-3336. Direct a subset of annotated FSNamesystem calls for audit logging.
      (cdouglas)
  12. HADOOP-3400. A new API FileSystem.deleteOnExit() that facilitates handling of temporary files in HDFS.
      (dhruba)
  13. HADOOP-4. Add fuse-dfs to contrib, permitting one to mount an HDFS filesystem on systems that support FUSE, e.g., Linux.
      (Pete Wyckoff via cutting)
  14. HADOOP-3246. Add FTPFileSystem.
      (Ankur Goel via cutting)
  15. HADOOP-3250. Extend FileSystem API to allow appending to files. (Tsz Wo (Nicholas), SZE via cdouglas)
  16. HADOOP-3177. Implement Syncable interface for FileSystem. (Tsz Wo (Nicholas), SZE via dhruba)
  17. HADOOP-1328. Implement user counters in streaming.
      (tomwhite via omalley)
  18. HADOOP-3187. Quotas for namespace management.
      (Hairong Kuang via ddas)
  19. HADOOP-3307. Support for Archives in Hadoop.
      (Mahadev Konar via ddas)
  20. HADOOP-3460. Add SequenceFileAsBinaryOutputFormat to permit direct writes of serialized data.
      (Koji Noguchi via cdouglas)
  21. HADOOP-3230. Add ability to get counter values from command line.
      (tomwhite via omalley)
  22. HADOOP-930. Add support for native S3 files.
      (tomwhite via cutting)
  23. HADOOP-3502. Quota API needs documentation in Forrest.
      (hairong)
  24. HADOOP-3413. Allow SequenceFile.Reader to use serialization framework.
      (tomwhite via omalley)
  25. HADOOP-3541. Import of the namespace from a checkpoint documented in hadoop user guide.
      (shv)
- IMPROVEMENTS (47)
  1. HADOOP-3677. Simplify generation stamp upgrade by making is a local upgrade on datandodes. Deleted distributed upgrade.
     (rangadi)
  2. HADOOP-2928. Remove deprecated FileSystem.getContentLength().
     (Lohit Vijayarenu via rangadi)
  3. HADOOP-3130. Make the connect timeout smaller for getFile.
     (Amar Ramesh Kamat via ddas)
  4. HADOOP-3160. Remove deprecated exists() from ClientProtocol and FSNamesystem
     (Lohit Vjayarenu via rangadi)
  5. HADOOP-2910. Throttle IPC Clients during bursts of requests or server slowdown. Clients retry connection for up to 15 minutes when socket connection times out.
     (hairong)
  6. HADOOP-3295. Allow TextOutputFormat to use configurable spearators. (Zheng Shao via cdouglas).
  7. HADOOP-3308. Improve QuickSort by excluding values eq the pivot from the partition.
     (cdouglas)
  8. HADOOP-2461. Trim property names in configuration. (Tsz Wo (Nicholas), SZE via shv)
  9. HADOOP-2799. Deprecate o.a.h.io.Closable in favor of java.io.Closable. (Tsz Wo (Nicholas), SZE via cdouglas)
  10. HADOOP-3345. Enhance the hudson-test-patch target to cleanup messages, fix minor defects, and add eclipse plugin and python unit tests.
      (nigel)
  11. HADOOP-3144. Improve robustness of LineRecordReader by defining a maximum line length (mapred.linerecordreader.maxlength), thereby avoiding reading too far into the following split.
      (Zheng Shao via cdouglas)
  12. HADOOP-3334. Move lease handling from FSNamesystem into a seperate class. (Tsz Wo (Nicholas), SZE via rangadi)
  13. HADOOP-3332. Reduces the amount of logging in Reducer's shuffle phase.
      (Devaraj Das)
  14. HADOOP-3355. Enhances Configuration class to accept hex numbers for getInt and getLong.
      (Amareshwari Sriramadasu via ddas)
  15. HADOOP-3350. Add an argument to distcp to permit the user to limit the number of maps.
      (cdouglas)
  16. HADOOP-3013. Add corrupt block reporting to fsck.
      (lohit vijayarenu via cdouglas)
  17. HADOOP-3377. Remove TaskRunner::replaceAll and replace with equivalent String::replace.
      (Brice Arnould via cdouglas)
  18. HADOOP-3398. Minor improvement to a utility function in that participates in backoff calculation.
      (cdouglas)
  19. HADOOP-3381. Clear referenced when directories are deleted so that effect of memory leaks are not multiplied.
      (rangadi)
  20. HADOOP-2867. Adds the task's CWD to its LD_LIBRARY_PATH.
      (Amareshwari Sriramadasu via ddas)
  21. HADOOP-3232. DU class runs the 'du' command in a seperate thread so that it does not block user. DataNode misses heartbeats in large nodes otherwise.
      (Johan Oskarsson via rangadi)
  22. HADOOP-3035. During block transfers between datanodes, the receiving datanode, now can report corrupt replicas received from src node to the namenode.
      (Lohit Vijayarenu via rangadi)
  23. HADOOP-3434. Retain the cause of the bind failure in Server::bind.
      (Steve Loughran via cdouglas)
  24. HADOOP-3429. Increases the size of the buffers used for the communication for Streaming jobs.
      (Amareshwari Sriramadasu via ddas)
  25. HADOOP-3486. Change default for initial block report to 0 seconds and document it.
      (Sanjay Radia via omalley)
  26. HADOOP-3448. Improve the text in the assertion making sure the layout versions are consistent in the data node.
      (Steve Loughran via omalley)
  27. HADOOP-2095. Improve the Map-Reduce shuffle/merge by cutting down buffer-copies; changed intermediate sort/merge to use the new IFile format rather than SequenceFiles and compression of map-outputs is now implemented by compressing the entire file rather than SequenceFile compression. Shuffle also has been changed to use a simple byte-buffer manager rather than the InMemoryFileSystem. Configuration changes to hadoop-default.xml: deprecated mapred.map.output.compression.type
      (acmurthy)
  28. HADOOP-236. JobTacker now refuses connection from a task tracker with a different version number.
      (Sharad Agarwal via ddas)
  29. HADOOP-3427. Improves the shuffle scheduler. It now waits for notifications from shuffle threads when it has scheduled enough, before scheduling more.
      (ddas)
  30. HADOOP-2393. Moves the handling of dir deletions in the tasktracker to a separate thread.
      (Amareshwari Sriramadasu via ddas)
  31. HADOOP-3501. Deprecate InMemoryFileSystem.
      (cutting via omalley)
  32. HADOOP-3366. Stall the shuffle while in-memory merge is in progress.
      (acmurthy)
  33. HADOOP-2916. Refactor src structure, but leave package structure alone.
      (Raghu Angadi via mukund)
  34. HADOOP-3492. Add forrest documentation for user archives.
      (Mahadev Konar via hairong)
  35. HADOOP-3467. Improve documentation for FileSystem::deleteOnExit. (Tsz Wo (Nicholas), SZE via cdouglas)
  36. HADOOP-3379. Documents stream.non.zero.exit.status.is.failure for Streaming.
      (Amareshwari Sriramadasu via ddas)
  37. HADOOP-3096. Improves documentation about the Task Execution Environment in the Map-Reduce tutorial.
      (Amareshwari Sriramadasu via ddas)
  38. HADOOP-2984. Add forrest documentation for DistCp.
      (cdouglas)
  39. HADOOP-3406. Add forrest documentation for Profiling.
      (Amareshwari Sriramadasu via ddas)
  40. HADOOP-2762. Add forrest documentation for controls of memory limits on hadoop daemons and Map-Reduce tasks.
      (Amareshwari Sriramadasu via ddas)
  41. HADOOP-3535. Fix documentation and name of IOUtils.close to reflect that it should only be used in cleanup contexts.
      (omalley)
  42. HADOOP-3593. Updates the mapred tutorial.
      (ddas)
  43. HADOOP-3547. Documents the way in which native libraries can be distributed via the DistributedCache.
      (Amareshwari Sriramadasu via ddas)
  44. HADOOP-3606. Updates the Streaming doc.
      (Amareshwari Sriramadasu via ddas)
  45. HADOOP-3532. Add jdiff reports to the build scripts.
      (omalley)
  46. HADOOP-3100. Develop tests to test the DFS command line interface.
      (mukund)
  47. HADOOP-3688. Fix up HDFS docs.
      (Robert Chansler via hairong)
- OPTIMIZATIONS (10)
  1. HADOOP-3274. The default constructor of BytesWritable creates empty byte array. (Tsz Wo (Nicholas), SZE via shv)
  2. HADOOP-3272. Remove redundant copy of Block object in BlocksMap.
     (Lohit Vjayarenu via shv)
  3. HADOOP-3164. Reduce DataNode CPU usage by using FileChannel.tranferTo(). On Linux DataNode takes 5 times less CPU while serving data. Results may vary on other platforms.
     (rangadi)
  4. HADOOP-3248. Optimization of saveFSImage.
     (Dhruba via shv)
  5. HADOOP-3297. Fetch more task completion events from the job tracker and task tracker.
     (ddas via omalley)
  6. HADOOP-3364. Faster image and log edits loading.
     (shv)
  7. HADOOP-3369. Fast block processing during name-node startup.
     (shv)
  8. HADOOP-1702. Reduce buffer copies when data is written to DFS. DataNodes take 30% less CPU while writing data.
     (rangadi)
  9. HADOOP-3095. Speed up split generation in the FileInputSplit, especially for non-HDFS file systems. Deprecates InputFormat.validateInput.
     (tomwhite via omalley)
  10. HADOOP-3552. Add forrest documentation for Hadoop commands.
      (Sharad Agarwal via cdouglas)
- BUG FIXES (144)
  1. HADOOP-2905. 'fsck -move' triggers NPE in NameNode.
     (Lohit Vjayarenu via rangadi)
  2. Increment ClientProtocol.versionID missed by HADOOP-2585.
     (shv)
  3. HADOOP-3254. Restructure internal namenode methods that process heartbeats to use well-defined BlockCommand object(s) instead of using the base java Object. (Tsz Wo (Nicholas), SZE via dhruba)
  4. HADOOP-3176. Change lease record when a open-for-write-file gets renamed.
     (dhruba)
  5. HADOOP-3269. Fix a case when namenode fails to restart while processing a lease record. ((Tsz Wo (Nicholas), SZE via dhruba)
  6. HADOOP-3282. Port issues in TestCheckpoint resolved.
     (shv)
  7. HADOOP-3268. file:// URLs issue in TestUrlStreamHandler under Windows.
     (taton)
  8. HADOOP-3127. Deleting files in trash should really remove them.
     (Brice Arnould via omalley)
  9. HADOOP-3300. Fix locking of explicit locks in NetworkTopology.
     (tomwhite via omalley)
  10. HADOOP-3270. Constant DatanodeCommands are stored in static final immutable variables for better code clarity. (Tsz Wo (Nicholas), SZE via dhruba)
  11. HADOOP-2793. Fix broken links for worst performing shuffle tasks in the job history page.
      (Amareshwari Sriramadasu via ddas)
  12. HADOOP-3313. Avoid unnecessary calls to System.currentTimeMillis in RPC::Invoker.
      (cdouglas)
  13. HADOOP-3318. Recognize "Darwin" as an alias for "Mac OS X" to support Soylatte.
      (Sam Pullara via omalley)
  14. HADOOP-3301. Fix misleading error message when S3 URI hostname contains an underscore.
      (tomwhite via omalley)
  15. HADOOP-3338. Fix Eclipse plugin to compile after HADOOP-544 was committed. Updated all references to use the new JobID representation.
      (taton via nigel)
  16. HADOOP-3337. Loading FSEditLog was broken by HADOOP-3283 since it changed Writable serialization of DatanodeInfo. This patch handles it. (Tsz Wo (Nicholas), SZE via rangadi)
  17. HADOOP-3101. Prevent JobClient from throwing an exception when printing usage.
      (Edward J. Yoon via cdouglas)
  18. HADOOP-3119. Update javadoc for Text::getBytes to better describe its behavior.
      (Tim Nelson via cdouglas)
  19. HADOOP-2294. Fix documentation in libhdfs to refer to the correct free function.
      (Craig Macdonald via cdouglas)
  20. HADOOP-3335. Prevent the libhdfs build from deleting the wrong files on make clean.
      (cutting via omalley)
  21. HADOOP-2930. Make {start,stop}-balancer.sh work even if hadoop-daemon.sh is not in the PATH.
      (Spiros Papadimitriou via hairong)
  22. HADOOP-3085. Catch Exception in metrics util classes to ensure that misconfigured metrics don't prevent others from updating.
      (cdouglas)
  23. HADOOP-3299. CompositeInputFormat should configure the sub-input formats.
      (cdouglas via omalley)
  24. HADOOP-3309. Lower io.sort.mb and fs.inmemory.size.mb for MiniMRDFSSort unit test so it passes on Windows.
      (lohit vijayarenu via cdouglas)
  25. HADOOP-3348. TestUrlStreamHandler should set URLStreamFactory after DataNodes are initialized.
      (Lohit Vijayarenu via rangadi)
  26. HADOOP-3371. Ignore InstanceAlreadyExistsException from MBeanUtil::registerMBean.
      (lohit vijayarenu via cdouglas)
  27. HADOOP-3349. A file rename was incorrectly changing the name inside a lease record. (Tsz Wo (Nicholas), SZE via dhruba)
  28. HADOOP-3365. Removes an unnecessary copy of the key from SegmentDescriptor to MergeQueue.
      (Devaraj Das)
  29. HADOOP-3388. Fix for TestDatanodeBlockScanner to handle blocks with generation stamps in them.
      (dhruba)
  30. HADOOP-3203. Fixes TaskTracker::localizeJob to pass correct file sizes for the jarfile and the jobfile.
      (Amareshwari Sriramadasu via ddas)
  31. HADOOP-3391. Fix a findbugs warning introduced by HADOOP-3248
      (rangadi)
  32. HADOOP-3393. Fix datanode shutdown to call DataBlockScanner::shutdown and close its log, even if the scanner thread is not running.
      (lohit vijayarenu via cdouglas)
  33. HADOOP-3399. A debug message was logged at info level.
      (rangadi)
  34. HADOOP-3396. TestDatanodeBlockScanner occationally fails.
      (Lohit Vijayarenu via rangadi)
  35. HADOOP-3339. Some of the failures on 3rd datanode in DFS write pipelie are not detected properly. This could lead to hard failure of client's write operation.
      (rangadi)
  36. HADOOP-3409. Namenode should save the root inode into fsimage.
      (hairong)
  37. HADOOP-3296. Fix task cache to work for more than two levels in the cache hierarchy. This also adds a new counter to track cache hits at levels greater than two.
      (Amar Kamat via cdouglas)
  38. HADOOP-3375. Lease paths were sometimes not removed from LeaseManager.sortedLeasesByPath. (Tsz Wo (Nicholas), SZE via dhruba)
  39. HADOOP-3424. Values returned by getPartition should be checked to make sure they are in the range 0 to #reduces - 1
      (cdouglas via omalley)
  40. HADOOP-3408. Change FSNamesystem to send its metrics as integers to accommodate collectors that don't support long values.
      (lohit vijayarenu via cdouglas)
  41. HADOOP-3403. Fixes a problem in the JobTracker to do with handling of lost tasktrackers.
      (Arun Murthy via ddas)
  42. HADOOP-1318. Completed maps are not failed if the number of reducers are zero. (Amareshwari Sriramadasu via ddas).
  43. HADOOP-3351. Fixes the history viewer tool to not do huge StringBuffer allocations.
      (Amareshwari Sriramadasu via ddas)
  44. HADOOP-3419. Fixes TestFsck to wait for updates to happen before checking results to make the test more reliable.
      (Lohit Vijaya Renu via omalley)
  45. HADOOP-3259. Makes failure to read system properties due to a security manager non-fatal.
      (Edward Yoon via omalley)
  46. HADOOP-3451. Update libhdfs to use FileSystem::getFileBlockLocations instead of removed getFileCacheHints.
      (lohit vijayarenu via cdouglas)
  47. HADOOP-3401. Update FileBench to set the new "mapred.work.output.dir" property to work post-3041.
      (cdouglas via omalley)
  48. HADOOP-2669. DFSClient locks pendingCreates appropriately.
      (dhruba)
  49. HADOOP-3410. Fix KFS implemenation to return correct file modification time.
      (Sriram Rao via cutting)
  50. HADOOP-3340. Fix DFS metrics for BlocksReplicated, HeartbeatsNum, and BlockReportsAverageTime.
      (lohit vijayarenu via cdouglas)
  51. HADOOP-3435. Remove the assuption in the scripts that bash is at /bin/bash and fix the test patch to require bash instead of sh.
      (Brice Arnould via omalley)
  52. HADOOP-3471. Fix spurious errors from TestIndexedSort and add additional logging to let failures be reproducible.
      (cdouglas)
  53. HADOOP-3443. Avoid copying map output across partitions when renaming a single spill.
      (omalley via cdouglas)
  54. HADOOP-3454. Fix Text::find to search only valid byte ranges.
      (Chad Whipkey via cdouglas)
  55. HADOOP-3417. Removes the static configuration variable, commandLineConfig from JobClient. Moves the cli parsing from JobShell to GenericOptionsParser. Thus removes the class org.apache.hadoop.mapred.JobShell.
      (Amareshwari Sriramadasu via ddas)
  56. HADOOP-2132. Only RUNNING/PREP jobs can be killed.
      (Jothi Padmanabhan via ddas)
  57. HADOOP-3476. Code cleanup in fuse-dfs.
      (Peter Wyckoff via dhruba)
  58. HADOOP-2427. Ensure that the cwd of completed tasks is cleaned-up correctly on task-completion.
      (Amareshwari Sri Ramadasu via acmurthy)
  59. HADOOP-2565. Remove DFSPath cache of FileStatus. (Tsz Wo (Nicholas), SZE via hairong)
  60. HADOOP-3326. Cleanup the local-fs and in-memory merge in the ReduceTask by spawing only one thread each for the on-disk and in-memory merge.
      (Sharad Agarwal via acmurthy)
  61. HADOOP-3493. Fix TestStreamingFailure to use FileUtil.fullyDelete to ensure correct cleanup.
      (Lohit Vijayarenu via acmurthy)
  62. HADOOP-3455. Fix NPE in ipc.Client in case of connection failure and improve its synchronization.
      (hairong)
  63. HADOOP-3240. Fix a testcase to not create files in the current directory. Instead the file is created in the test directory
      (Mahadev Konar via ddas)
  64. HADOOP-3496. Fix failure in TestHarFileSystem.testArchives due to change in HADOOP-3095.
      (tomwhite)
  65. HADOOP-3135. Get the system directory from the JobTracker instead of from the conf.
      (Subramaniam Krishnan via ddas)
  66. HADOOP-3503. Fix a race condition when client and namenode start simultaneous recovery of the same block. (dhruba & Tsz Wo (Nicholas), SZE)
  67. HADOOP-3440. Fixes DistributedCache to not create symlinks for paths which don't have fragments even when createSymLink is true.
      (Abhijit Bagri via ddas)
  68. HADOOP-3463. Hadoop-daemons script should cd to $HADOOP_HOME.
      (omalley)
  69. HADOOP-3489. Fix NPE in SafeModeMonitor.
      (Lohit Vijayarenu via shv)
  70. HADOOP-3509. Fix NPE in FSNamesystem.close. (Tsz Wo (Nicholas), SZE via shv)
  71. HADOOP-3491. Name-node shutdown causes InterruptedException in ResolutionMonitor.
      (Lohit Vijayarenu via shv)
  72. HADOOP-3511. Fixes namenode image to not set the root's quota to an invalid value when the quota was not saved in the image.
      (hairong)
  73. HADOOP-3516. Ensure the JobClient in HadoopArchives is initialized with a configuration.
      (Subramaniam Krishnan via omalley)
  74. HADOOP-3513. Improve NNThroughputBenchmark log messages.
      (shv)
  75. HADOOP-3519. Fix NPE in DFS FileSystem rename.
      (hairong via tomwhite)
  76. HADOOP-3528. Metrics FilesCreated and files_deleted metrics do not match.
      (Lohit via Mahadev)
  77. HADOOP-3418. When a directory is deleted, any leases that point to files in the subdirectory are removed. ((Tsz Wo (Nicholas), SZE via dhruba)
  78. HADOOP-3542. Diables the creation of _logs directory for the archives directory.
      (Mahadev Konar via ddas)
  79. HADOOP-3544. Fixes a documentation issue for hadoop archives.
      (Mahadev Konar via ddas)
  80. HADOOP-3517. Fixes a problem in the reducer due to which the last InMemory merge may be missed.
      (Arun Murthy via ddas)
  81. HADOOP-3548. Fixes build.xml to copy all *.jar files to the dist.
      (Owen O'Malley via ddas)
  82. HADOOP-3363. Fix unformatted storage detection in FSImage.
      (shv)
  83. HADOOP-3560. Fixes a problem to do with split creation in archives.
      (Mahadev Konar via ddas)
  84. HADOOP-3545. Fixes a overflow problem in archives.
      (Mahadev Konar via ddas)
  85. HADOOP-3561. Prevent the trash from deleting its parent directories.
      (cdouglas)
  86. HADOOP-3575. Fix the clover ant target after package refactoring.
      (Nigel Daley via cdouglas)
  87. HADOOP-3539. Fix the tool path in the bin/hadoop script under cygwin. (Tsz Wo (Nicholas), Sze via omalley)
  88. HADOOP-3520. TestDFSUpgradeFromImage triggers a race condition in the Upgrade Manager. Fixed.
      (dhruba)
  89. HADOOP-3586. Provide deprecated, backwards compatibile semantics for the combiner to be run once and only once on each record.
      (cdouglas)
  90. HADOOP-3533. Add deprecated methods to provide API compatibility between 0.18 and 0.17. Remove the deprecated methods in trunk.
      (omalley)
  91. HADOOP-3580. Fixes a problem to do with specifying a har as an input to a job.
      (Mahadev Konar via ddas)
  92. HADOOP-3333. Don't assign a task to a tasktracker that it failed to execute earlier (used to happen in the case of lost tasktrackers where the tasktracker would reinitialize and bind to a different port).
      (Jothi Padmanabhan and Arun Murthy via ddas)
  93. HADOOP-3534. Log IOExceptions that happen in closing the name system when the NameNode shuts down. (Tsz Wo (Nicholas) Sze via omalley)
  94. HADOOP-3546. TaskTracker re-initialization gets stuck in cleaning up.
      (Amareshwari Sriramadasu via ddas)
  95. HADOOP-3576. Fix NullPointerException when renaming a directory to its subdirectory. (Tse Wo (Nicholas), SZE via hairong)
  96. HADOOP-3320. Fix NullPointerException in NetworkTopology.getDistance().
      (hairong)
  97. HADOOP-3569. KFS input stream read() now correctly reads 1 byte instead of 4.
      (Sriram Rao via omalley)
  98. HADOOP-3599. Fix JobConf::setCombineOnceOnly to modify the instance rather than a parameter.
      (Owen O'Malley via cdouglas)
  99. HADOOP-3590. Null pointer exception in JobTracker when the task tracker is not yet resolved.
      (Amar Ramesh Kamat via ddas)
  100. HADOOP-3603. Fix MapOutputCollector to spill when io.sort.spill.percent is 1.0 and to detect spills when emitted records write no data.
       (cdouglas)
  101. HADOOP-3615. Set DatanodeProtocol.versionID to the correct value. (Tsz Wo (Nicholas), SZE via cdouglas)
  102. HADOOP-3559. Fix the libhdfs test script and config to work with the current semantics.
       (lohit vijayarenu via cdouglas)
  103. HADOOP-3480. Need to update Eclipse template to reflect current trunk.
       (Brice Arnould via tomwhite)
  104. HADOOP-3588. Fixed usability issues with archives.
       (mahadev)
  105. HADOOP-3635. Uncaught exception in DataBlockScanner. (Tsz Wo (Nicholas), SZE via hairong)
  106. HADOOP-3639. Exception when closing DFSClient while multiple files are open.
       (Benjamin Gufler via hairong)
  107. HADOOP-3572. SetQuotas usage interface has some minor bugs.
       (hairong)
  108. HADOOP-3649. Fix bug in removing blocks from the corrupted block map.
       (Lohit Vijayarenu via shv)
  109. HADOOP-3604. Work around a JVM synchronization problem observed while retrieving the address of direct buffers from compression code by obtaining a lock during this call.
       (Arun C Murthy via cdouglas)
  110. HADOOP-3683. Fix dfs metrics to count file listings rather than files listed.
       (lohit vijayarenu via cdouglas)
  111. HADOOP-3597. Fix SortValidator to use filesystems other than the default as input. Validation job still runs on default fs.
       (Jothi Padmanabhan via cdouglas)
  112. HADOOP-3693. Fix archives, distcp and native library documentation to conform to style guidelines.
       (Amareshwari Sriramadasu via cdouglas)
  113. HADOOP-3653. Fix test-patch target to properly account for Eclipse classpath jars.
       (Brice Arnould via nigel)
  114. HADOOP-3692. Fix documentation for Cluster setup and Quick start guides.
       (Amareshwari Sriramadasu via ddas)
  115. HADOOP-3691. Fix streaming and tutorial docs.
       (Jothi Padmanabhan via ddas)
  116. HADOOP-3630. Fix NullPointerException in CompositeRecordReader from empty sources
       (cdouglas)
  117. HADOOP-3706. Fix a ClassLoader issue in the mapred.join Parser that prevents it from loading user-specified InputFormats.
       (Jingkei Ly via cdouglas)
  118. HADOOP-3718. Fix KFSOutputStream::write(int) to output a byte instead of an int, per the OutputStream contract.
       (Sriram Rao via cdouglas)
  119. HADOOP-3647. Add debug logs to help track down a very occassional, hard-to-reproduce, bug in shuffle/merge on the reducer.
       (acmurthy)
  120. HADOOP-3716. Prevent listStatus in KosmosFileSystem from returning null for valid, empty directories.
       (Sriram Rao via cdouglas)
  121. HADOOP-3752. Fix audit logging to record rename events.
       (cdouglas)
  122. HADOOP-3737. Fix CompressedWritable to call Deflater::end to release compressor memory.
       (Grant Glouser via cdouglas)
  123. HADOOP-3670. Fixes JobTracker to clear out split bytes when no longer required.
       (Amareshwari Sriramadasu via ddas)
  124. HADOOP-3755. Update gridmix to work with HOD 0.4
       (Runping Qi via cdouglas)
  125. HADOOP-3743. Fix -libjars, -files, -archives options to work even if user code does not implement tools.
       (Amareshwari Sriramadasu via mahadev)
  126. HADOOP-3774. Fix typos in shell output. (Tsz Wo (Nicholas), SZE via cdouglas)
  127. HADOOP-3762. Fixed FileSystem cache to work with the default port.
       (cutting via omalley)
  128. HADOOP-3798. Fix tests compilation.
       (Mukund Madhugiri via omalley)
  129. HADOOP-3794. Return modification time instead of zero for KosmosFileSystem.
       (Sriram Rao via cdouglas)
  130. HADOOP-3806. Remove debug statement to stdout from QuickSort.
       (cdouglas)
  131. HADOOP-3776. Fix NPE at NameNode when datanode reports a block after it is deleted at NameNode.
       (rangadi)
  132. HADOOP-3537. Disallow adding a datanode to a network topology when its network location is not resolved.
       (hairong)
  133. HADOOP-3571. Fix bug in block removal used in lease recovery.
       (shv)
  134. HADOOP-3645. MetricsTimeVaryingRate returns wrong value for metric_avg_time.
       (Lohit Vijayarenu via hairong)
  135. HADOOP-3521. Reverted the missing cast to float for sending Counters' values to Hadoop metrics which was removed by HADOOP-544.
       (acmurthy)
  136. HADOOP-3820. Fixes two problems in the gridmix-env - a syntax error, and a wrong definition of USE_REAL_DATASET by default.
       (Arun Murthy via ddas)
  137. HADOOP-3724. Fixes two problems related to storing and recovering lease in the fsimage.
       (dhruba)
  138. HADOOP-3827. Fixed compression of empty map-outputs.
       (acmurthy)
  139. HADOOP-3865. Remove reference to FSNamesystem from metrics preventing garbage collection.
       (Lohit Vijayarenu via cdouglas)
  140. HADOOP-3884. Fix so that Eclipse plugin builds against recent Eclipse releases.
       (cutting)
  141. HADOOP-3837. Streaming jobs report progress status.
       (dhruba)
  142. HADOOP-3897. Fix a NPE in secondary namenode.
       (Lohit Vijayarenu via cdouglas)
  143. HADOOP-3901. Fix bin/hadoop to correctly set classpath under cygwin. (Tsz Wo (Nicholas) Sze via omalley)
  144. HADOOP-3947. Fix a problem in tasktracker reinitialization.
       (Amareshwari Sriramadasu via ddas)

### Release 0.17.3 - Unreleased

- IMPROVEMENTS (1)
  1. HADOOP-4164. Chinese translation of the documentation.
     (Xuebing Yan via omalley)
- BUG FIXES (4)
  1. HADOOP-4277. Checksum verification was mistakenly disabled for LocalFileSystem.
     (Raghu Angadi)
  2. HADOOP-4271. Checksum input stream can sometimes return invalid data to the user.
     (Ning Li via rangadi)
  3. HADOOP-4318. DistCp should use absolute paths for cleanup.
     (szetszwo)
  4. HADOOP-4326. ChecksumFileSystem does not override create(...) correctly.
     (szetszwo)

### Release 0.17.2 - 2008-08-11

- BUG FIXES (12)
  1. HADOOP-3678. Avoid spurious exceptions logged at DataNode when clients read from DFS.
     (rangadi)
  2. HADOOP-3707. NameNode keeps a count of number of blocks scheduled to be written to a datanode and uses it to avoid allocating more blocks than a datanode can hold.
     (rangadi)
  3. HADOOP-3760. Fix a bug with HDFS file close() mistakenly introduced by HADOOP-3681.
     (Lohit Vijayarenu via rangadi)
  4. HADOOP-3681. DFSClient can get into an infinite loop while closing a file if there are some errors.
     (Lohit Vijayarenu via rangadi)
  5. HADOOP-3002. Hold off block removal while in safe mode.
     (shv)
  6. HADOOP-3685. Unbalanced replication target.
     (hairong)
  7. HADOOP-3758. Shutdown datanode on version mismatch instead of retrying continuously, preventing excessive logging at the namenode.
     (lohit vijayarenu via cdouglas)
  8. HADOOP-3633. Correct exception handling in DataXceiveServer, and throttle the number of xceiver threads in a data-node.
     (shv)
  9. HADOOP-3370. Ensure that the TaskTracker.runningJobs data-structure is correctly cleaned-up on task completion.
     (Zheng Shao via acmurthy)
  10. HADOOP-3813. Fix task-output clean-up on HDFS to use the recursive FileSystem.delete rather than the FileUtil.fullyDelete.
      (Amareshwari Sri Ramadasu via acmurthy)
  11. HADOOP-3859. Allow the maximum number of xceivers in the data node to be configurable.
      (Johan Oskarsson via omalley)
  12. HADOOP-3931. Fix corner case in the map-side sort that causes some values to be counted as too large and cause pre-mature spills to disk. Some values will also bypass the combiner incorrectly.
      (cdouglas via omalley)

### Release 0.17.1 - 2008-06-23

- INCOMPATIBLE CHANGES (1)
  1. HADOOP-3565. Fix the Java serialization, which is not enabled by default, to clear the state of the serializer between objects.
     (tomwhite via omalley)
- IMPROVEMENTS (2)
  1. HADOOP-3522. Improve documentation on reduce pointing out that input keys and values will be reused.
     (omalley)
  2. HADOOP-3487. Balancer uses thread pools for managing its threads; therefore provides better resource management.
     (hairong)
- BUG FIXES (8)
  1. HADOOP-2159 Namenode stuck in safemode. The counter blockSafe should not be decremented for invalid blocks.
     (hairong)
  2. HADOOP-3472 MapFile.Reader getClosest() function returns incorrect results when before is true
     (Todd Lipcon via Stack)
  3. HADOOP-3442. Limit recursion depth on the stack for QuickSort to prevent StackOverflowErrors. To avoid O(n*n) cases, when partitioning depth exceeds a multiple of log(n), change to HeapSort.
     (cdouglas)
  4. HADOOP-3477. Fix build to not package contrib/*/bin twice in distributions.
     (Adam Heath via cutting)
  5. HADOOP-3475. Fix MapTask to correctly size the accounting allocation of io.sort.mb.
     (cdouglas)
  6. HADOOP-3550. Fix the serialization data structures in MapTask where the value lengths are incorrectly calculated.
     (cdouglas)
  7. HADOOP-3526. Fix contrib/data_join framework by cloning values retained in the reduce.
     (Spyros Blanas via cdouglas)
  8. HADOOP-1979. Speed up fsck by adding a buffered stream.
     (Lohit Vijaya Renu via omalley)

### Release 0.17.0 - 2008-05-18

- INCOMPATIBLE CHANGES (26)
  1. HADOOP-2786. Move hbase out of hadoop core
  2. HADOOP-2345. New HDFS transactions to support appending to files. Disk layout version changed from -11 to -12.
     (dhruba)
  3. HADOOP-2192. Error messages from "dfs mv" command improved.
     (Mahadev Konar via dhruba)
  4. HADOOP-1902. "dfs du" command without any arguments operates on the current working directory.
     (Mahadev Konar via dhruba)
  5. HADOOP-2873. Fixed bad disk format introduced by HADOOP-2345. Disk layout version changed from -12 to -13. See changelist 630992
     (dhruba)
  6. HADOOP-1985. This addresses rack-awareness for Map tasks and for HDFS in a uniform way.
     (ddas)
  7. HADOOP-1986. Add support for a general serialization mechanism for Map Reduce.
     (tomwhite)
  8. HADOOP-771. FileSystem.delete() takes an explicit parameter that specifies whether a recursive delete is intended.
     (Mahadev Konar via dhruba)
  9. HADOOP-2470. Remove getContentLength(String), open(String, long, long) and isDir(String) from ClientProtocol. ClientProtocol version changed from 26 to 27. (Tsz Wo (Nicholas), SZE via cdouglas)
  10. HADOOP-2822. Remove deprecated code for classes InputFormatBase and PhasedFileSystem.
      (Amareshwari Sriramadasu via enis)
  11. HADOOP-2116. Changes the layout of the task execution directory.
      (Amareshwari Sriramadasu via ddas)
  12. HADOOP-2828. The following deprecated methods in Configuration.java have been removed getObject(String name) setObject(String name, Object value) get(String name, Object defaultValue) set(String name, Object value) Iterator entries()
      (Amareshwari Sriramadasu via ddas)
  13. HADOOP-2824. Removes one deprecated constructor from MiniMRCluster.
      (Amareshwari Sriramadasu via ddas)
  14. HADOOP-2823. Removes deprecated methods getColumn(), getLine() from org.apache.hadoop.record.compiler.generated.SimpleCharStream.
      (Amareshwari Sriramadasu via ddas)
  15. HADOOP-3060. Removes one unused constructor argument from MiniMRCluster.
      (Amareshwari Sriramadasu via ddas)
  16. HADOOP-2854. Remove deprecated o.a.h.ipc.Server::getUserInfo().
      (lohit vijayarenu via cdouglas)
  17. HADOOP-2563. Remove deprecated FileSystem::listPaths.
      (lohit vijayarenu via cdouglas)
  18. HADOOP-2818. Remove deprecated methods in Counters.
      (Amareshwari Sriramadasu via tomwhite)
  19. HADOOP-2831. Remove deprecated o.a.h.dfs.INode::getAbsoluteName()
      (lohit vijayarenu via cdouglas)
  20. HADOOP-2839. Remove deprecated FileSystem::globPaths.
      (lohit vijayarenu via cdouglas)
  21. HADOOP-2634. Deprecate ClientProtocol::exists.
      (lohit vijayarenu via cdouglas)
  22. HADOOP-2410. Make EC2 cluster nodes more independent of each other. Multiple concurrent EC2 clusters are now supported, and nodes may be added to a cluster on the fly with new nodes starting in the same EC2 availability zone as the cluster. Ganglia monitoring and large instance sizes have also been added.
      (Chris K Wensel via tomwhite)
  23. HADOOP-2826. Deprecated FileSplit.getFile(), LineRecordReader.readLine().
      (Amareshwari Sriramadasu via ddas)
  24. HADOOP-3239. getFileInfo() returns null for non-existing files instead of throwing FileNotFoundException.
      (Lohit Vijayarenu via shv)
  25. HADOOP-3266. Removed HOD changes from CHANGES.txt, as they are now inside src/contrib/hod
      (Hemanth Yamijala via ddas)
  26. HADOOP-3280. Separate the configuration of the virtual memory size (mapred.child.ulimit) from the jvm heap size, so that 64 bit streaming applications are supported even when running with 32 bit jvms.
      (acmurthy via omalley)
- NEW FEATURES (12)
  1. HADOOP-1398. Add HBase in-memory block cache.
     (tomwhite)
  2. HADOOP-2178. Job History on DFS.
     (Amareshwari Sri Ramadasu via ddas)
  3. HADOOP-2063. A new parameter to dfs -get command to fetch a file even if it is corrupted. (Tsz Wo (Nicholas), SZE via dhruba)
  4. HADOOP-2219. A new command "df -count" that counts the number of files and directories. (Tsz Wo (Nicholas), SZE via dhruba)
  5. HADOOP-2906. Add an OutputFormat capable of using keys, values, and config params to map records to different output files.
     (Runping Qi via cdouglas)
  6. HADOOP-2346. Utilities to support timeout while writing to sockets. DFSClient and DataNode sockets have 10min write timeout.
     (rangadi)
  7. HADOOP-2951. Add a contrib module that provides a utility to build or update Lucene indexes using Map/Reduce.
     (Ning Li via cutting)
  8. HADOOP-1622. Allow multiple jar files for map reduce.
     (Mahadev Konar via dhruba)
  9. HADOOP-2055. Allows users to set PathFilter on the FileInputFormat.
     (Alejandro Abdelnur via ddas)
  10. HADOOP-2551. More environment variables like HADOOP_NAMENODE_OPTS for better control of HADOOP_OPTS for each component.
      (rangadi)
  11. HADOOP-3001. Add job counters that measure the number of bytes read and written to HDFS, S3, KFS, and local file systems.
      (omalley)
  12. HADOOP-3048. A new Interface and a default implementation to convert and restore serializations of objects to/from strings.
      (enis)
- IMPROVEMENTS (29)
  1. HADOOP-2655. Copy on write for data and metadata files in the presence of snapshots. Needed for supporting appends to HDFS files.
     (dhruba)
  2. HADOOP-1967. When a Path specifies the same scheme as the default FileSystem but no authority, the default FileSystem's authority is used. Also add warnings for old-format FileSystem names, accessor methods for fs.default.name, and check for null authority in HDFS.
     (cutting)
  3. HADOOP-2895. Let the profiling string be configurable.
     (Martin Traverso via cdouglas)
  4. HADOOP-910. Enables Reduces to do merges for the on-disk map output files in parallel with their copying.
     (Amar Kamat via ddas)
  5. HADOOP-730. Use rename rather than copy for local renames.
     (cdouglas)
  6. HADOOP-2810. Updated the Hadoop Core logo.
     (nigel)
  7. HADOOP-2057. Streaming should optionally treat a non-zero exit status of a child process as a failed task.
     (Rick Cox via tomwhite)
  8. HADOOP-2765. Enables specifying ulimits for streaming/pipes tasks
     (ddas)
  9. HADOOP-2888. Make gridmix scripts more readily configurable and amenable to automated execution.
     (Mukund Madhugiri via cdouglas)
  10. HADOOP-2908. A document that describes the DFS Shell command.
      (Mahadev Konar via dhruba)
  11. HADOOP-2981. Update README.txt to reflect the upcoming use of cryptography.
      (omalley)
  12. HADOOP-2804. Add support to publish CHANGES.txt as HTML when running the Ant 'docs' target.
      (nigel)
  13. HADOOP-2559. Change DFS block placement to allocate the first replica locally, the second off-rack, and the third intra-rack from the second.
      (lohit vijayarenu via cdouglas)
  14. HADOOP-2939. Make the automated patch testing process an executable Ant target, test-patch.
      (nigel)
  15. HADOOP-2239. Add HsftpFileSystem to permit transferring files over ssl.
      (cdouglas)
  16. HADOOP-2886. Track individual RPC metrics.
      (girish vaitheeswaran via dhruba)
  17. HADOOP-2373. Improvement in safe-mode reporting.
      (shv)
  18. HADOOP-3091. Modify FsShell command -put to accept multiple sources.
      (Lohit Vijaya Renu via cdouglas)
  19. HADOOP-3092. Show counter values from job -status command.
      (Tom White via ddas)
  20. HADOOP-1228. Ant task to generate Eclipse project files.
      (tomwhite)
  21. HADOOP-3093. Adds Configuration.getStrings(name, default-value) and the corresponding setStrings.
      (Amareshwari Sriramadasu via ddas)
  22. HADOOP-3106. Adds documentation in forrest for debugging.
      (Amareshwari Sriramadasu via ddas)
  23. HADOOP-3099. Add an option to distcp to preserve user, group, and permission information. (Tsz Wo (Nicholas), SZE via cdouglas)
  24. HADOOP-2841. Unwrap AccessControlException and FileNotFoundException from RemoteException for DFSClient.
      (shv)
  25. HADOOP-3152. Make index interval configuable when using MapFileOutputFormat for map-reduce job.
      (Rong-En Fan via cutting)
  26. HADOOP-3143. Decrease number of slaves from 4 to 3 in TestMiniMRDFSSort, as Hudson generates false negatives under the current load.
      (Nigel Daley via cdouglas)
  27. HADOOP-3174. Illustrative example for MultipleFileInputFormat.
      (Enis Soztutar via acmurthy)
  28. HADOOP-2993. Clarify the usage of JAVA_HOME in the Quick Start guide.
      (acmurthy via nigel)
  29. HADOOP-3124. Make DataNode socket write timeout configurable.
      (rangadi)
- OPTIMIZATIONS (12)
  1. HADOOP-2790. Fixed inefficient method hasSpeculativeTask by removing repetitive calls to get the current time and late checking to see if we want speculation on at all.
     (omalley)
  2. HADOOP-2758. Reduce buffer copies in DataNode when data is read from HDFS, without negatively affecting read throughput.
     (rangadi)
  3. HADOOP-2399. Input key and value to combiner and reducer is reused. (Owen O'Malley via ddas).
  4. HADOOP-2423. Code optimization in FSNamesystem.mkdirs. (Tsz Wo (Nicholas), SZE via dhruba)
  5. HADOOP-2606. ReplicationMonitor selects data-nodes to replicate directly from needed replication blocks instead of looking up for the blocks for each live data-node.
     (shv)
  6. HADOOP-2148. Eliminate redundant data-node blockMap lookups.
     (shv)
  7. HADOOP-2027. Return the number of bytes in each block in a file via a single rpc to the namenode to speed up job planning.
     (Lohit Vijaya Renu via omalley)
  8. HADOOP-2902. Replace uses of "fs.default.name" with calls to the accessor methods added in HADOOP-1967.
     (cutting)
  9. HADOOP-2119. Optimize scheduling of jobs with large numbers of tasks by replacing static arrays with lists of runnable tasks.
     (Amar Kamat via omalley)
  10. HADOOP-2919. Reduce the number of memory copies done during the map output sorting. Also adds two config variables: io.sort.spill.percent - the percentages of io.sort.mb that should cause a spill (default 80%) io.sort.record.percent - the percent of io.sort.mb that should hold key/value indexes (default 5%)
      (cdouglas via omalley)
  11. HADOOP-3140. Doesn't add a task in the commit queue if the task hadn't generated any output.
      (Amar Kamat via ddas)
  12. HADOOP-3168. Reduce the amount of logging in streaming to an exponentially increasing number of records (up to 10,000 records/log).
      (Zheng Shao via omalley)
- BUG FIXES (102)
  1. HADOOP-2195. '-mkdir' behaviour is now closer to Linux shell in case of errors.
     (Mahadev Konar via rangadi)
  2. HADOOP-2190. bring behaviour '-ls' and '-du' closer to Linux shell commands in case of errors.
     (Mahadev Konar via rangadi)
  3. HADOOP-2193. 'fs -rm' and 'fs -rmr' show error message when the target file does not exist.
     (Mahadev Konar via rangadi)
  4. HADOOP-2738 Text is not subclassable because set(Text) and compareTo(Object) access the other instance's private members directly.
     (jimk)
  5. HADOOP-2779. Remove the references to HBase in the build.xml.
     (omalley)
  6. HADOOP-2194. dfs cat on a non-existent file throws FileNotFoundException.
     (Mahadev Konar via dhruba)
  7. HADOOP-2767. Fix for NetworkTopology erroneously skipping the last leaf node on a rack.
     (Hairong Kuang and Mark Butler via dhruba)
  8. HADOOP-1593. FsShell works with paths in non-default FileSystem.
     (Mahadev Konar via dhruba)
  9. HADOOP-2191. du and dus command on non-existent directory gives appropriate error message.
     (Mahadev Konar via dhruba)
  10. HADOOP-2832. Remove tabs from code of DFSClient for better indentation.
      (dhruba)
  11. HADOOP-2844. distcp closes file handles for sequence files. (Tsz Wo (Nicholas), SZE via dhruba)
  12. HADOOP-2727. Fix links in Web UI of the hadoop daemons and some docs
      (Amareshwari Sri Ramadasu via ddas)
  13. HADOOP-2871. Fixes a problem to do with file: URI in the JobHistory init.
      (Amareshwari Sri Ramadasu via ddas)
  14. HADOOP-2800. Deprecate SetFile.Writer constructor not the whole class.
      (Johan Oskarsson via tomwhite)
  15. HADOOP-2891. DFSClient.close() closes all open files.
      (dhruba)
  16. HADOOP-2845. Fix dfsadmin disk utilization report on Solaris.
      (Martin Traverso via tomwhite)
  17. HADOOP-2912. MiniDFSCluster restart should wait for namenode to exit safemode. This was causing TestFsck to fail.
      (Mahadev Konar via dhruba)
  18. HADOOP-2820. The following classes in streaming are removed : StreamLineRecordReader StreamOutputFormat StreamSequenceRecordReader.
      (Amareshwari Sri Ramadasu via ddas)
  19. HADOOP-2819. The following methods in JobConf are removed: getInputKeyClass() setInputKeyClass getInputValueClass() setInputValueClass(Class theClass) setSpeculativeExecution getSpeculativeExecution()
      (Amareshwari Sri Ramadasu via ddas)
  20. HADOOP-2817. Removes deprecated mapred.tasktracker.tasks.maximum and ClusterStatus.getMaxTasks().
      (Amareshwari Sri Ramadasu via ddas)
  21. HADOOP-2821. Removes deprecated ShellUtil and ToolBase classes from the util package.
      (Amareshwari Sri Ramadasu via ddas)
  22. HADOOP-2934. The namenode was encountreing a NPE while loading leases from the fsimage. Fixed.
      (dhruba)
  23. HADOOP-2938. Some fs commands did not glob paths. (Tsz Wo (Nicholas), SZE via rangadi)
  24. HADOOP-2943. Compression of intermediate map output causes failures in the merge.
      (cdouglas)
  25. HADOOP-2870. DataNode and NameNode closes all connections while shutting down.
      (Hairong Kuang via dhruba)
  26. HADOOP-2973. Fix TestLocalDFS for Windows platform. (Tsz Wo (Nicholas), SZE via dhruba)
  27. HADOOP-2971. select multiple times if it returns early in SocketIOWithTimeout.
      (rangadi)
  28. HADOOP-2955. Fix TestCrcCorruption test failures caused by HADOOP-2758
      (rangadi)
  29. HADOOP-2657. A flush call on the DFSOutputStream flushes the last partial CRC chunk too.
      (dhruba)
  30. HADOOP-2974. IPC unit tests used "0.0.0.0" to connect to server, which is not always supported.
      (rangadi)
  31. HADOOP-2996. Fixes uses of StringBuffer in StreamUtils class.
      (Dave Brosius via ddas)
  32. HADOOP-2995. Fixes StreamBaseRecordReader's getProgress to return a floating point number.
      (Dave Brosius via ddas)
  33. HADOOP-2972. Fix for a NPE in FSDataset.invalidate.
      (Mahadev Konar via dhruba)
  34. HADOOP-2994. Code cleanup for DFSClient: remove redundant conversions from string to string.
      (Dave Brosius via dhruba)
  35. HADOOP-3009. TestFileCreation sometimes fails because restarting minidfscluster sometimes creates datanodes with ports that are different from their original instance.
      (dhruba)
  36. HADOOP-2992. Distributed Upgrade framework works correctly with more than one upgrade object.
      (Konstantin Shvachko via dhruba)
  37. HADOOP-2679. Fix a typo in libhdfs.
      (Jason via dhruba)
  38. HADOOP-2976. When a lease expires, the Namenode ensures that blocks of the file are adequately replicated.
      (dhruba)
  39. HADOOP-2901. Fixes the creation of info servers in the JobClient and JobTracker. Removes the creation from JobClient and removes additional info server from the JobTracker. Also adds the command line utility to view the history files (HADOOP-2896), and fixes bugs in JSPs to do with analysis - HADOOP-2742, HADOOP-2792.
      (Amareshwari Sri Ramadasu via ddas)
  40. HADOOP-2890. If different datanodes report the same block but with different sizes to the namenode, the namenode picks the replica(s) with the largest size as the only valid replica(s).
      (dhruba)
  41. HADOOP-2825. Deprecated MapOutputLocation.getFile() is removed.
      (Amareshwari Sri Ramadasu via ddas)
  42. HADOOP-2806. Fixes a streaming document.
      (Amareshwari Sriramadasu via ddas)
  43. HADOOP-3008. SocketIOWithTimeout throws InterruptedIOException if the thread is interrupted while it is waiting.
      (rangadi)
  44. HADOOP-3006. Fix wrong packet size reported by DataNode when a block is being replicated.
      (rangadi)
  45. HADOOP-3029. Datanode prints log message "firstbadlink" only if it detects a bad connection to another datanode in the pipeline.
      (dhruba)
  46. HADOOP-3030. Release reserved space for file in InMemoryFileSystem if checksum reservation fails.
      (Devaraj Das via cdouglas)
  47. HADOOP-3036. Fix findbugs warnings in UpgradeUtilities.
      (Konstantin Shvachko via cdouglas)
  48. HADOOP-3025. ChecksumFileSystem supports the delete method with the recursive flag.
      (Mahadev Konar via dhruba)
  49. HADOOP-3012. dfs -mv file to user home directory throws exception if the user home directory does not exist.
      (Mahadev Konar via dhruba)
  50. HADOOP-3066. Should not require superuser privilege to query if hdfs is in safe mode
      (jimk)
  51. HADOOP-3040. If the input line starts with the separator char, the key is set as empty.
      (Amareshwari Sriramadasu via ddas)
  52. HADOOP-3080. Removes flush calls from JobHistory.
      (Amareshwari Sriramadasu via ddas)
  53. HADOOP-3086. Adds the testcase missed during commit of hadoop-3040.
      (Amareshwari Sriramadasu via ddas)
  54. HADOOP-3046. Fix the raw comparators for Text and BytesWritables to use the provided length rather than recompute it.
      (omalley)
  55. HADOOP-3094. Fix BytesWritable.toString to avoid extending the sign bit
      (Owen O'Malley via cdouglas)
  56. HADOOP-3067. DFSInputStream's position read does not close the sockets.
      (rangadi)
  57. HADOOP-3073. close() on SocketInputStream or SocketOutputStream should close the underlying channel.
      (rangadi)
  58. HADOOP-3087. Fixes a problem to do with refreshing of loadHistory.jsp.
      (Amareshwari Sriramadasu via ddas)
  59. HADOOP-3065. Better logging message if the rack location of a datanode cannot be determined.
      (Devaraj Das via dhruba)
  60. HADOOP-3064. Commas in a file path should not be treated as delimiters.
      (Hairong Kuang via shv)
  61. HADOOP-2997. Adds test for non-writable serialier. Also fixes a problem introduced by HADOOP-2399.
      (Tom White via ddas)
  62. HADOOP-3114. Fix TestDFSShell on Windows.
      (Lohit Vijaya Renu via cdouglas)
  63. HADOOP-3118. Fix Namenode NPE while loading fsimage after a cluster upgrade from older disk format.
      (dhruba)
  64. HADOOP-3161. Fix FIleUtil.HardLink.getLinkCount on Mac OS.
      (nigel via omalley)
  65. HADOOP-2927. Fix TestDU to acurately calculate the expected file size.
      (shv via nigel)
  66. HADOOP-3123. Fix the native library build scripts to work on Solaris.
      (tomwhite via omalley)
  67. HADOOP-3089. Streaming should accept stderr from task before first key arrives.
      (Rick Cox via tomwhite)
  68. HADOOP-3146. A DFSOutputStream.flush method is renamed as DFSOutputStream.fsync.
      (dhruba)
  69. HADOOP-3165. -put/-copyFromLocal did not treat input file "-" as stdin.
      (Lohit Vijayarenu via rangadi)
  70. HADOOP-3041. Deprecate JobConf.setOutputPath and JobConf.getOutputPath. Deprecate OutputFormatBase. Add FileOutputFormat. Existing output formats extending OutputFormatBase, now extend FileOutputFormat. Add the following APIs in FileOutputFormat: setOutputPath, getOutputPath, getWorkOutputPath.
      (Amareshwari Sriramadasu via nigel)
  71. HADOOP-3083. The fsimage does not store leases. This would have to be reworked in the next release to support appends.
      (dhruba)
  72. HADOOP-3166. Fix an ArrayIndexOutOfBoundsException in the spill thread and make exception handling more promiscuous to catch this condition.
      (cdouglas)
  73. HADOOP-3050. DataNode sends one and only one block report after it registers with the namenode.
      (Hairong Kuang)
  74. HADOOP-3044. NNBench sets the right configuration for the mapper.
      (Hairong Kuang)
  75. HADOOP-3178. Fix GridMix scripts for small and medium jobs to handle input paths differently.
      (Mukund Madhugiri via nigel)
  76. HADOOP-1911. Fix an infinite loop in DFSClient when all replicas of a block are bad
      (cdouglas)
  77. HADOOP-3157. Fix path handling in DistributedCache and TestMiniMRLocalFS.
      (Doug Cutting via rangadi)
  78. HADOOP-3018. Fix the eclipse plug-in contrib wrt removed deprecated methods
      (taton)
  79. HADOOP-3183. Fix TestJobShell to use 'ls' instead of java.io.File::exists since cygwin symlinks are unsupported.
      (Mahadev konar via cdouglas)
  80. HADOOP-3175. Fix FsShell.CommandFormat to handle "-" in arguments.
      (Edward J. Yoon via rangadi)
  81. HADOOP-3220. Safemode message corrected.
      (shv)
  82. HADOOP-3208. Fix WritableDeserializer to set the Configuration on deserialized Writables.
      (Enis Soztutar via cdouglas)
  83. HADOOP-3224. 'dfs -du /dir' does not return correct size.
      (Lohit Vjayarenu via rangadi)
  84. HADOOP-3223. Fix typo in help message for -chmod.
      (rangadi)
  85. HADOOP-1373. checkPath() should ignore case when it compares authoriy.
      (Edward J. Yoon via rangadi)
  86. HADOOP-3204. Fixes a problem to do with ReduceTask's LocalFSMerger not catching Throwable.
      (Amar Ramesh Kamat via ddas)
  87. HADOOP-3229. Report progress when collecting records from the mapper and the combiner.
      (Doug Cutting via cdouglas)
  88. HADOOP-3225. Unwrapping methods of RemoteException should initialize detailedMassage field.
      (Mahadev Konar, shv, cdouglas)
  89. HADOOP-3247. Fix gridmix scripts to use the correct globbing syntax and change maxentToSameCluster to run the correct number of jobs.
      (Runping Qi via cdouglas)
  90. HADOOP-3242. Fix the RecordReader of SequenceFileAsBinaryInputFormat to correctly read from the start of the split and not the beginning of the file.
      (cdouglas via acmurthy)
  91. HADOOP-3256. Encodes the job name used in the filename for history files.
      (Arun Murthy via ddas)
  92. HADOOP-3162. Ensure that comma-separated input paths are treated correctly as multiple input paths.
      (Amareshwari Sri Ramadasu via acmurthy)
  93. HADOOP-3263. Ensure that the job-history log file always follows the pattern of hostname_timestamp_jobid_username_jobname even if username and/or jobname are not specfied. This helps to avoid wrong assumptions made about the job-history log filename in jobhistory.jsp.
      (acmurthy)
  94. HADOOP-3251. Fixes getFilesystemName in JobTracker and LocalJobRunner to use FileSystem.getUri instead of FileSystem.getName.
      (Arun Murthy via ddas)
  95. HADOOP-3237. Fixes TestDFSShell.testErrOutPut on Windows platform.
      (Mahadev Konar via ddas)
  96. HADOOP-3279. TaskTracker checks for SUCCEEDED task status in addition to COMMIT_PENDING status when it fails maps due to lost map.
      (Devaraj Das)
  97. HADOOP-3286. Prevent collisions in gridmix output dirs by increasing the granularity of the timestamp.
      (Runping Qi via cdouglas)
  98. HADOOP-3285. Fix input split locality when the splits align to fs blocks.
      (omalley)
  99. HADOOP-3372. Fix heap management in streaming tests.
      (Arun Murthy via cdouglas)
  100. HADOOP-3031. Fix javac warnings in test classes.
       (cdouglas)
  101. HADOOP-3382. Fix memory leak when files are not cleanly closed
       (rangadi)
  102. HADOOP-3322. Fix to push MetricsRecord for rpc metrics.
       (Eric Yang via mukund)

### Release 0.16.4 - 2008-05-05

- BUG FIXES (3)
  1. HADOOP-3138. DFS mkdirs() should not throw an exception if the directory already exists.
     (rangadi via mukund)
  2. HADOOP-3294. Fix distcp to check the destination length and retry the copy if it doesn't match the src length. (Tsz Wo (Nicholas), SZE via mukund)
  3. HADOOP-3186. Fix incorrect permission checkding for mv and renameTo in HDFS. (Tsz Wo (Nicholas), SZE via mukund)

### Release 0.16.3 - 2008-04-16

- BUG FIXES (7)
  1. HADOOP-3010. Fix ConcurrentModificationException in ipc.Server.Responder.
     (rangadi)
  2. HADOOP-3154. Catch all Throwables from the SpillThread in MapTask, rather than IOExceptions only.
     (ddas via cdouglas)
  3. HADOOP-3159. Avoid file system cache being overwritten whenever configuration is modified. (Tsz Wo (Nicholas), SZE via hairong)
  4. HADOOP-3139. Remove the consistency check for the FileSystem cache in closeAll() that causes spurious warnings and a deadlock. (Tsz Wo (Nicholas), SZE via cdouglas)
  5. HADOOP-3195. Fix TestFileSystem to be deterministic. (Tsz Wo (Nicholas), SZE via cdouglas)
  6. HADOOP-3069. Primary name-node should not truncate image when transferring it from the secondary.
     (shv)
  7. HADOOP-3182. Change permissions of the job-submission directory to 777 from 733 to ensure sharing of HOD clusters works correctly. (Tsz Wo (Nicholas), Sze and Amareshwari Sri Ramadasu via acmurthy)

### Release 0.16.2 - 2008-04-02

- BUG FIXES (18)
  1. HADOOP-3011. Prohibit distcp from overwriting directories on the destination filesystem with files.
     (cdouglas)
  2. HADOOP-3033. The BlockReceiver thread in the datanode writes data to the block file, changes file position (if needed) and flushes all by itself. The PacketResponder thread does not flush block file.
     (dhruba)
  3. HADOOP-2978. Fixes the JobHistory log format for counters.
     (Runping Qi via ddas)
  4. HADOOP-2985. Fixes LocalJobRunner to tolerate null job output path. Also makes the _temporary a constant in MRConstants.java.
     (Amareshwari Sriramadasu via ddas)
  5. HADOOP-3003. FileSystem cache key is updated after a FileSystem object is created. (Tsz Wo (Nicholas), SZE via dhruba)
  6. HADOOP-3042. Updates the Javadoc in JobConf.getOutputPath to reflect the actual temporary path.
     (Amareshwari Sriramadasu via ddas)
  7. HADOOP-3007. Tolerate mirror failures while DataNode is replicating blocks as it used to before.
     (rangadi)
  8. HADOOP-2944. Fixes a "Run on Hadoop" wizard NPE when creating a Location from the wizard.
     (taton)
  9. HADOOP-3049. Fixes a problem in MultiThreadedMapRunner to do with catching RuntimeExceptions.
     (Alejandro Abdelnur via ddas)
  10. HADOOP-3039. Fixes a problem to do with exceptions in tasks not killing jobs.
      (Amareshwari Sriramadasu via ddas)
  11. HADOOP-3027. Fixes a problem to do with adding a shutdown hook in FileSystem.
      (Amareshwari Sriramadasu via ddas)
  12. HADOOP-3056. Fix distcp when the target is an empty directory by making sure the directory is created first.
      (cdouglas and acmurthy via omalley)
  13. HADOOP-3070. Protect the trash emptier thread from null pointer exceptions.
      (Koji Noguchi via omalley)
  14. HADOOP-3084. Fix HftpFileSystem to work for zero-lenghth files.
      (cdouglas)
  15. HADOOP-3107. Fix NPE when fsck invokes getListings.
      (dhruba)
  16. HADOOP-3104. Limit MultithreadedMapRunner to have a fixed length queue between the RecordReader and the map threads.
      (Alejandro Abdelnur via omalley)
  17. HADOOP-2833. Do not use "Dr. Who" as the default user in JobClient. A valid user name is required. (Tsz Wo (Nicholas), SZE via rangadi)
  18. HADOOP-3128. Throw RemoteException in setPermissions and setOwner of DistributedFileSystem.
      (shv via nigel)

### Release 0.16.1 - 2008-03-13

- INCOMPATIBLE CHANGES (1)
  1. HADOOP-2869. Deprecate SequenceFile.setCompressionType in favor of SequenceFile.createWriter, SequenceFileOutputFormat.setCompressionType, and JobConf.setMapOutputCompressionType. (Arun C Murthy via cdouglas) Configuration changes to hadoop-default.xml: deprecated io.seqfile.compression.type
- IMPROVEMENTS (2)
  1. HADOOP-2371. User guide for file permissions in HDFS.
     (Robert Chansler via rangadi)
  2. HADOOP-3098. Allow more characters in user and group names while using -chown and -chgrp commands.
     (rangadi)
- BUG FIXES (31)
  1. HADOOP-2789. Race condition in IPC Server Responder that could close connections early.
     (Raghu Angadi)
  2. HADOOP-2785. minor. Fix a typo in Datanode block verification
     (Raghu Angadi)
  3. HADOOP-2788. minor. Fix help message for chgrp shell command (Raghu Angadi).
  4. HADOOP-1188. fstime file is updated when a storage directory containing namespace image becomes inaccessible.
     (shv)
  5. HADOOP-2787. An application can set a configuration variable named dfs.umask to set the umask that is used by DFS. (Tsz Wo (Nicholas), SZE via dhruba)
  6. HADOOP-2780. The default socket buffer size for DataNodes is 128K.
     (dhruba)
  7. HADOOP-2716. Superuser privileges for the Balancer. (Tsz Wo (Nicholas), SZE via shv)
  8. HADOOP-2754. Filter out .crc files from local file system listing.
     (Hairong Kuang via shv)
  9. HADOOP-2733. Fix compiler warnings in test code. (Tsz Wo (Nicholas), SZE via cdouglas)
  10. HADOOP-2725. Modify distcp to avoid leaving partially copied files at the destination after encountering an error. (Tsz Wo (Nicholas), SZE via cdouglas)
  11. HADOOP-2391. Cleanup job output directory before declaring a job as SUCCESSFUL.
      (Amareshwari Sri Ramadasu via ddas)
  12. HADOOP-2808. Minor fix to FileUtil::copy to mind the overwrite formal.
      (cdouglas)
  13. HADOOP-2683. Moving UGI out of the RPC Server. (Tsz Wo (Nicholas), SZE via shv)
  14. HADOOP-2814. Fix for NPE in datanode in unit test TestDataTransferProtocol.
      (Raghu Angadi via dhruba)
  15. HADOOP-2811. Dump of counters in job history does not add comma between groups.
      (runping via omalley)
  16. HADOOP-2735. Enables setting TMPDIR for tasks.
      (Amareshwari Sri Ramadasu via ddas)
  17. HADOOP-2843. Fix protections on map-side join classes to enable derivation.
      (cdouglas via omalley)
  18. HADOOP-2840. Fix gridmix scripts to correctly invoke the java sort through the proper jar.
      (Mukund Madhugiri via cdouglas)
  19. HADOOP-2769. TestNNThroughputBnechmark should not use a fixed port for the namenode http port.
      (omalley)
  20. HADOOP-2852. Update gridmix benchmark to avoid an artifically long tail.
      (cdouglas)
  21. HADOOP-2894. Fix a problem to do with tasktrackers failing to connect to JobTracker upon reinitialization. (Owen O'Malley via ddas).
  22. HADOOP-2903. Fix exception generated by Metrics while using pushMetric().
      (girish vaitheeswaran via dhruba)
  23. HADOOP-2904. Fix to RPC metrics to log the correct host name.
      (girish vaitheeswaran via dhruba)
  24. HADOOP-2918. Improve error logging so that dfs writes failure with "No lease on file" can be diagnosed.
      (dhruba)
  25. HADOOP-2923. Add SequenceFileAsBinaryInputFormat, which was missed in the commit for HADOOP-2603.
      (cdouglas via omalley)
  26. HADOOP-2931. IOException thrown by DFSOutputStream had wrong stack trace in some cases.
      (Michael Bieniosek via rangadi)
  27. HADOOP-2883. Write failures and data corruptions on HDFS files. The write timeout is back to what it was on 0.15 release. Also, the datnodes flushes the block file buffered output stream before sending a positive ack for the packet back to the client.
      (dhruba)
  28. HADOOP-2756. NPE in DFSClient while closing DFSOutputStreams under load.
      (rangadi)
  29. HADOOP-2958. Fixed FileBench which broke due to HADOOP-2391 which performs a check for existence of the output directory and a trivial bug in GenericMRLoadGenerator where min/max word lenghts were identical since they were looking at the same config variables
      (Chris Douglas via acmurthy)
  30. HADOOP-2915. Fixed FileSystem.CACHE so that a username is included in the cache key. (Tsz Wo (Nicholas), SZE via nigel)
  31. HADOOP-2813. TestDU unit test uses its own directory to run its sequence of tests.
      (Mahadev Konar via dhruba)

### Release 0.16.0 - 2008-02-07

- INCOMPATIBLE CHANGES (14)
  1. HADOOP-1245. Use the mapred.tasktracker.tasks.maximum value configured on each tasktracker when allocating tasks, instead of the value configured on the jobtracker. InterTrackerProtocol version changed from 5 to 6.
     (Michael Bieniosek via omalley)
  2. HADOOP-1843. Removed code from Configuration and JobConf deprecated by HADOOP-785 and a minor fix to Configuration.toString. Specifically the important change is that mapred-default.xml is no longer supported and Configuration no longer supports the notion of default/final resources.
     (acmurthy)
  3. HADOOP-1302. Remove deprecated abacus code from the contrib directory. This also fixes a configuration bug in AggregateWordCount, so that the job now works.
     (enis)
  4. HADOOP-2288. Enhance FileSystem API to support access control. (Tsz Wo (Nicholas), SZE via dhruba)
  5. HADOOP-2184. RPC Support for user permissions and authentication.
     (Raghu Angadi via dhruba)
  6. HADOOP-2185. RPC Server uses any available port if the specified port is zero. Otherwise it uses the specified port. Also combines the configuration attributes for the servers' bind address and port from "x.x.x.x" and "y" to "x.x.x.x:y". Deprecated configuration variables: dfs.info.bindAddress dfs.info.port dfs.datanode.bindAddress dfs.datanode.port dfs.datanode.info.bindAdress dfs.datanode.info.port dfs.secondary.info.bindAddress dfs.secondary.info.port mapred.job.tracker.info.bindAddress mapred.job.tracker.info.port mapred.task.tracker.report.bindAddress tasktracker.http.bindAddress tasktracker.http.port New configuration variables (post HADOOP-2404): dfs.secondary.http.address dfs.datanode.address dfs.datanode.http.address dfs.http.address mapred.job.tracker.http.address mapred.task.tracker.report.address mapred.task.tracker.http.address
     (Konstantin Shvachko via dhruba)
  7. HADOOP-2401. Only the current leaseholder can abandon a block for a HDFS file. ClientProtocol version changed from 20 to 21. (Tsz Wo (Nicholas), SZE via dhruba)
  8. HADOOP-2381. Support permission information in FileStatus. Client Protocol version changed from 21 to 22.
     (Raghu Angadi via dhruba)
  9. HADOOP-2110. Block report processing creates fewer transient objects. Datanode Protocol version changed from 10 to 11.
     (Sanjay Radia via dhruba)
  10. HADOOP-2567. Add FileSystem#getHomeDirectory(), which returns the user's home directory in a FileSystem as a fully-qualified path. FileSystem#getWorkingDirectory() is also changed to return a fully-qualified path, which can break applications that attempt to, e.g., pass LocalFileSystem#getWorkingDir().toString() directly to java.io methods that accept file names.
      (cutting)
  11. HADOOP-2514. Change trash feature to maintain a per-user trash directory, named ".Trash" in the user's home directory. The "fs.trash.root" parameter is no longer used. Full source paths are also no longer reproduced within the trash.
  12. HADOOP-2012. Periodic data verification on Datanodes.
      (Raghu Angadi via dhruba)
  13. HADOOP-1707. The DFSClient does not use a local disk file to cache writes to a HDFS file. Changed Data Transfer Version from 7 to 8.
      (dhruba)
  14. HADOOP-2652. Fix permission issues for HftpFileSystem. This is an incompatible change since distcp may not be able to copy files from cluster A (compiled with this patch) to cluster B (compiled with previous versions). (Tsz Wo (Nicholas), SZE via dhruba)
- NEW FEATURES (13)
  1. HADOOP-1857. Ability to run a script when a task fails to capture stack traces.
     (Amareshwari Sri Ramadasu via ddas)
  2. HADOOP-2299. Defination of a login interface. A simple implementation for Unix users and groups.
     (Hairong Kuang via dhruba)
  3. HADOOP-1652. A utility to balance data among datanodes in a HDFS cluster.
     (Hairong Kuang via dhruba)
  4. HADOOP-2085. A library to support map-side joins of consistently partitioned and sorted data sets.
     (Chris Douglas via omalley)
  5. HADOOP-2336. Shell commands to modify file permissions.
     (rangadi)
  6. HADOOP-1298. Implement file permissions for HDFS. (Tsz Wo (Nicholas) & taton via cutting)
  7. HADOOP-2447. HDFS can be configured to limit the total number of objects (inodes and blocks) in the file system.
     (dhruba)
  8. HADOOP-2487. Added an option to get statuses for all submitted/run jobs. This information can be used to develop tools for analysing jobs.
     (Amareshwari Sri Ramadasu via acmurthy)
  9. HADOOP-1873. Implement user permissions for Map/Reduce framework.
     (Hairong Kuang via shv)
  10. HADOOP-2532. Add to MapFile a getClosest method that returns the key that comes just before if the key is not present.
      (stack via tomwhite)
  11. HADOOP-1883. Add versioning to Record I/O.
      (Vivek Ratan via ddas)
  12. HADOOP-2603. Add SeqeunceFileAsBinaryInputFormat, which reads sequence files as BytesWritable/BytesWritable regardless of the key and value types used to write the file.
      (cdouglas via omalley)
  13. HADOOP-2367. Add ability to profile a subset of map/reduce tasks and fetch the result to the local filesystem of the submitting application. Also includes a general IntegerRanges extension to Configuration for setting positive, ranged parameters.
      (Owen O'Malley via cdouglas)
- IMPROVEMENTS (54)
  1. HADOOP-2045. Change committer list on website to a table, so that folks can list their organization, timezone, etc.
     (cutting)
  2. HADOOP-2058. Facilitate creating new datanodes dynamically in MiniDFSCluster.
     (Hairong Kuang via dhruba)
  3. HADOOP-1855. fsck verifies block placement policies and reports violations.
     (Konstantin Shvachko via dhruba)
  4. HADOOP-1604. An system administrator can finalize namenode upgrades without running the cluster.
     (Konstantin Shvachko via dhruba)
  5. HADOOP-1839. Link-ify the Pending/Running/Complete/Killed grid in jobdetails.jsp to help quickly narrow down and see categorized TIPs' details via jobtasks.jsp.
     (Amar Kamat via acmurthy)
  6. HADOOP-1210. Log counters in job history.
     (Owen O'Malley via ddas)
  7. HADOOP-1912. Datanode has two new commands COPY and REPLACE. These are needed for supporting data rebalance.
     (Hairong Kuang via dhruba)
  8. HADOOP-2086. This patch adds the ability to add dependencies to a job (run via JobControl) after construction.
     (Adrian Woodhead via ddas)
  9. HADOOP-1185. Support changing the logging level of a server without restarting the server. (Tsz Wo (Nicholas), SZE via dhruba)
  10. HADOOP-2134. Remove developer-centric requirements from overview.html and keep it end-user focussed, specifically sections related to subversion and building Hadoop.
      (Jim Kellerman via acmurthy)
  11. HADOOP-1989. Support simulated DataNodes. This helps creating large virtual clusters for testing purposes.
      (Sanjay Radia via dhruba)
  12. HADOOP-1274. Support different number of mappers and reducers per TaskTracker to allow administrators to better configure and utilize heterogenous clusters. Configuration changes to hadoop-default.xml: add mapred.tasktracker.map.tasks.maximum (default value of 2) add mapred.tasktracker.reduce.tasks.maximum (default value of 2) remove mapred.tasktracker.tasks.maximum (deprecated for 0.16.0)
      (Amareshwari Sri Ramadasu via acmurthy)
  13. HADOOP-2104. Adds a description to the ant targets. This makes the output of "ant -projecthelp" sensible.
      (Chris Douglas via ddas)
  14. HADOOP-2127. Added a pipes sort example to benchmark trivial pipes application versus trivial java application.
      (omalley via acmurthy)
  15. HADOOP-2113. A new shell command "dfs -text" to view the contents of a gziped or SequenceFile.
      (Chris Douglas via dhruba)
  16. HADOOP-2207. Add a "package" target for contrib modules that permits each to determine what files are copied into release builds.
      (stack via cutting)
  17. HADOOP-1984. Makes the backoff for failed fetches exponential. Earlier, it was a random backoff from an interval.
      (Amar Kamat via ddas)
  18. HADOOP-1327. Include website documentation for streaming.
      (Rob Weltman via omalley)
  19. HADOOP-2000. Rewrite NNBench to measure namenode performance accurately. It now uses the map-reduce framework for load generation.
      (Mukund Madhugiri via dhruba)
  20. HADOOP-2248. Speeds up the framework w.r.t Counters. Also has API updates to the Counters part.
      (Owen O'Malley via ddas)
  21. HADOOP-2326. The initial block report at Datanode startup time has a random backoff period.
      (Sanjay Radia via dhruba)
  22. HADOOP-2432. HDFS includes the name of the file while throwing "File does not exist" exception.
      (Jim Kellerman via dhruba)
  23. HADOOP-2457. Added a 'forrest.home' property to the 'docs' target in build.xml.
      (acmurthy)
  24. HADOOP-2149. A new benchmark for three name-node operation: file create, open, and block report, to evaluate the name-node performance for optimizations or new features.
      (Konstantin Shvachko via shv)
  25. HADOOP-2466. Change FileInputFormat.computeSplitSize to a protected non-static method to allow sub-classes to provide alternate implementations.
      (Alejandro Abdelnur via acmurthy)
  26. HADOOP-2425. Change TextOutputFormat to handle Text specifically for better performance. Make NullWritable implement Comparable. Make TextOutputFormat treat NullWritable like null.
      (omalley)
  27. HADOOP-1719. Improves the utilization of shuffle copier threads.
      (Amar Kamat via ddas)
  28. HADOOP-2390. Added documentation for user-controls for intermediate map-outputs & final job-outputs and native-hadoop libraries.
      (acmurthy)
  29. HADOOP-1660. Add the cwd of the map/reduce task to the java.library.path of the child-jvm to support loading of native libraries distributed via the DistributedCache.
      (acmurthy)
  30. HADOOP-2285. Speeds up TextInputFormat. Also includes updates to the Text API.
      (Owen O'Malley via cdouglas)
  31. HADOOP-2233. Adds a generic load generator for modeling MR jobs.
      (cdouglas)
  32. HADOOP-2369. Adds a set of scripts for simulating a mix of user map/reduce workloads.
      (Runping Qi via cdouglas)
  33. HADOOP-2547. Removes use of a 'magic number' in build.xml.
      (Hrishikesh via nigel)
  34. HADOOP-2268. Fix org.apache.hadoop.mapred.jobcontrol classes to use the List/Map interfaces rather than concrete ArrayList/HashMap classes internally.
      (Adrian Woodhead via acmurthy)
  35. HADOOP-2406. Add a benchmark for measuring read/write performance through the InputFormat interface, particularly with compression.
      (cdouglas)
  36. HADOOP-2131. Allow finer-grained control over speculative-execution. Now users can set it for maps and reduces independently. Configuration changes to hadoop-default.xml: deprecated mapred.speculative.execution add mapred.map.tasks.speculative.execution add mapred.reduce.tasks.speculative.execution
      (Amareshwari Sri Ramadasu via acmurthy)
  37. HADOOP-1965. Interleave sort/spill in teh map-task along with calls to the Mapper.map method. This is done by splitting the 'io.sort.mb' buffer into two and using one half for collecting map-outputs and the other half for sort/spill.
      (Amar Kamat via acmurthy)
  38. HADOOP-2464. Unit tests for chmod, chown, and chgrp using DFS.
      (Raghu Angadi)
  39. HADOOP-1876. Persist statuses of completed jobs in HDFS so that the JobClient can query and get information about decommissioned jobs and also across JobTracker restarts. Configuration changes to hadoop-default.xml: add mapred.job.tracker.persist.jobstatus.active (default value of false) add mapred.job.tracker.persist.jobstatus.hours (default value of 0) add mapred.job.tracker.persist.jobstatus.dir (default value of /jobtracker/jobsInfo)
      (Alejandro Abdelnur via acmurthy)
  40. HADOOP-2077. Added version and build information to STARTUP_MSG for all hadoop daemons to aid error-reporting, debugging etc.
      (acmurthy)
  41. HADOOP-2398. Additional instrumentation for NameNode and RPC server. Add support for accessing instrumentation statistics via JMX.
      (Sanjay radia via dhruba)
  42. HADOOP-2449. A return of the non-MR version of NNBench.
      (Sanjay Radia via shv)
  43. HADOOP-1989. Remove 'datanodecluster' command from bin/hadoop.
      (Sanjay Radia via shv)
  44. HADOOP-1742. Improve JavaDoc documentation for ClientProtocol, DFSClient, and FSNamesystem.
      (Konstantin Shvachko)
  45. HADOOP-2298. Add Ant target for a binary-only distribution.
      (Hrishikesh via nigel)
  46. HADOOP-2509. Add Ant target for Rat report (Apache license header reports).
      (Hrishikesh via nigel)
  47. HADOOP-2469. WritableUtils.clone should take a Configuration instead of a JobConf.
      (stack via omalley)
  48. HADOOP-2659. Introduce superuser permissions for admin operations. (Tsz Wo (Nicholas), SZE via shv)
  49. HADOOP-2596. Added a SequenceFile.createWriter api which allows the user to specify the blocksize, replication factor and the buffersize to be used for the underlying HDFS file.
      (Alejandro Abdelnur via acmurthy)
  50. HADOOP-2431. Test HDFS File Permissions.
      (Hairong Kuang via shv)
  51. HADOOP-2232. Add an option to disable Nagle's algorithm in the IPC stack.
      (Clint Morgan via cdouglas)
  52. HADOOP-2342. Created a micro-benchmark for measuring local-file versus hdfs reads.
      (Owen O'Malley via nigel)
  53. HADOOP-2529. First version of HDFS User Guide.
      (Raghu Angadi)
  54. HADOOP-2690. Add jar-test target to build.xml, separating compilation and packaging of the test classes.
      (Enis Soztutar via cdouglas)
- OPTIMIZATIONS (4)
  1. HADOOP-1898. Release the lock protecting the last time of the last stack dump while the dump is happening.
     (Amareshwari Sri Ramadasu via omalley)
  2. HADOOP-1900. Makes the heartbeat and task event queries interval dependent on the cluster size.
     (Amareshwari Sri Ramadasu via ddas)
  3. HADOOP-2208. Counter update frequency (from TaskTracker to JobTracker) is capped at 1 minute.
     (Amareshwari Sri Ramadasu via ddas)
  4. HADOOP-2284. Reduce the number of progress updates during the sorting in the map task.
     (Amar Kamat via ddas)
- BUG FIXES (90)
  1. HADOOP-2583. Fixes a bug in the Eclipse plug-in UI to edit locations. Plug-in version is now synchronized with Hadoop version.
  2. HADOOP-2100. Remove faulty check for existence of $HADOOP_PID_DIR and let 'mkdir -p' check & create it.
     (Michael Bieniosek via acmurthy)
  3. HADOOP-1642. Ensure jobids generated by LocalJobRunner are unique to avoid collissions and hence job-failures.
     (Doug Cutting via acmurthy)
  4. HADOOP-2096. Close open file-descriptors held by streams while localizing job.xml in the JobTracker and while displaying it on the webui in jobconf.jsp.
     (Amar Kamat via acmurthy)
  5. HADOOP-2098. Log start & completion of empty jobs to JobHistory, which also ensures that we close the file-descriptor of the job's history log opened during job-submission.
     (Amar Kamat via acmurthy)
  6. HADOOP-2112. Adding back changes to build.xml lost while reverting HADOOP-1622 i.e. http://svn.apache.org/viewvc?view=rev&revision=588771.
     (acmurthy)
  7. HADOOP-2089. Fixes the command line argument handling to handle multiple -cacheArchive in Hadoop streaming.
     (Lohit Vijayarenu via ddas)
  8. HADOOP-2071. Fix StreamXmlRecordReader to use a BufferedInputStream wrapped over the DFSInputStream since mark/reset aren't supported by DFSInputStream anymore.
     (Lohit Vijayarenu via acmurthy)
  9. HADOOP-1348. Allow XML comments inside configuration files.
     (Rajagopal Natarajan and Enis Soztutar via enis)
  10. HADOOP-1952. Improve handling of invalid, user-specified classes while configuring streaming jobs such as combiner, input/output formats etc. Now invalid options are caught, logged and jobs are failed early.
      (Lohit Vijayarenu via acmurthy)
  11. HADOOP-2151. FileSystem.globPaths validates the list of Paths that it returns.
      (Lohit Vijayarenu via dhruba)
  12. HADOOP-2121. Cleanup DFSOutputStream when the stream encountered errors when Datanodes became full.
      (Raghu Angadi via dhruba)
  13. HADOOP-1130. The FileSystem.closeAll() method closes all existing DFSClients.
      (Chris Douglas via dhruba)
  14. HADOOP-2204. DFSTestUtil.waitReplication was not waiting for all replicas to get created, thus causing unit test failure.
      (Raghu Angadi via dhruba)
  15. HADOOP-2078. An zero size file may have no blocks associated with it.
      (Konstantin Shvachko via dhruba)
  16. HADOOP-2212. ChecksumFileSystem.getSumBufferSize might throw java.lang.ArithmeticException. The fix is to initialize bytesPerChecksum to 0.
      (Michael Bieniosek via ddas)
  17. HADOOP-2216. Fix jobtasks.jsp to ensure that it first collects the taskids which satisfy the filtering criteria and then use that list to print out only the required task-reports, previously it was oblivious to the filtering and hence used the wrong index into the array of task-reports.
      (Amar Kamat via acmurthy)
  18. HADOOP-2272. Fix findbugs target to reflect changes made to the location of the streaming jar file by HADOOP-2207.
      (Adrian Woodhead via nigel)
  19. HADOOP-2244. Fixes the MapWritable.readFields to clear the instance field variable every time readFields is called. (Michael Stack via ddas).
  20. HADOOP-2245. Fixes LocalJobRunner to include a jobId in the mapId. Also, adds a testcase for JobControl. (Adrian Woodhead via ddas).
  21. HADOOP-2275. Fix erroneous detection of corrupted file when namenode fails to allocate any datanodes for newly allocated block.
      (Dhruba Borthakur via dhruba)
  22. HADOOP-2256. Fix a buf in the namenode that could cause it to encounter an infinite loop while deleting excess replicas that were created by block rebalancing.
      (Hairong Kuang via dhruba)
  23. HADOOP-2209. SecondaryNamenode process exits if it encounters exceptions that it cannot handle.
      (Dhruba Borthakur via dhruba)
  24. HADOOP-2314. Prevent TestBlockReplacement from occasionally getting into an infinite loop.
      (Hairong Kuang via dhruba)
  25. HADOOP-2300. This fixes a bug where mapred.tasktracker.tasks.maximum would be ignored even if it was set in hadoop-site.xml.
      (Amareshwari Sri Ramadasu via ddas)
  26. HADOOP-2349. Improve code layout in file system transaction logging code. (Tsz Wo (Nicholas), SZE via dhruba)
  27. HADOOP-2368. Fix unit tests on Windows. (Tsz Wo (Nicholas), SZE via dhruba)
  28. HADOOP-2363. This fix allows running multiple instances of the unit test in parallel. The bug was introduced in HADOOP-2185 that changed port-rolling behaviour.
      (Konstantin Shvachko via dhruba)
  29. HADOOP-2271. Fix chmod task to be non-parallel.
      (Adrian Woodhead via omalley)
  30. HADOOP-2313. Fail the build if building libhdfs fails.
      (nigel via omalley)
  31. HADOOP-2359. Remove warning for interruptted exception when closing down minidfs.
      (dhruba via omalley)
  32. HADOOP-1841. Prevent slow clients from consuming threads in the NameNode.
      (dhruba)
  33. HADOOP-2323. JobTracker.close() should not print stack traces for normal exit.
      (jimk via cutting)
  34. HADOOP-2376. Prevents sort example from overriding the number of maps.
      (Owen O'Malley via ddas)
  35. HADOOP-2434. FSDatasetInterface read interface causes HDFS reads to occur in 1 byte chunks, causing performance degradation.
      (Raghu Angadi via dhruba)
  36. HADOOP-2459. Fix package target so that src/docs/build files are not included in the release.
      (nigel)
  37. HADOOP-2215. Fix documentation in cluster_setup.html & mapred_tutorial.html reflect that mapred.tasktracker.tasks.maximum has been superceeded by mapred.tasktracker.{map|reduce}.tasks.maximum.
      (Amareshwari Sri Ramadasu via acmurthy)
  38. HADOOP-2459. Fix package target so that src/docs/build files are not included in the release.
      (nigel)
  39. HADOOP-2352. Remove AC_CHECK_LIB for libz and liblzo to ensure that libhadoop.so doesn't have a dependency on them.
      (acmurthy)
  40. HADOOP-2453. Fix the configuration for wordcount-simple example in Hadoop Pipes which currently produces an XML parsing error.
      (Amareshwari Sri Ramadasu via acmurthy)
  41. HADOOP-2476. Unit test failure while reading permission bits of local file system (on Windows) fixed.
      (Raghu Angadi via dhruba)
  42. HADOOP-2247. Fine-tune the strategies for killing mappers and reducers due to failures while fetching map-outputs. Now the map-completion times and number of currently running reduces are taken into account by the JobTracker before killing the mappers, while the progress made by the reducer and the number of fetch-failures vis-a-vis total number of fetch-attempts are taken into account before teh reducer kills itself.
      (Amar Kamat via acmurthy)
  43. HADOOP-2452. Fix eclipse plug-in build.xml to refers to the right location where hadoop-*-core.jar is generated.
      (taton)
  44. HADOOP-2492. Additional debugging in the rpc server to better diagnose ConcurrentModificationException.
      (dhruba)
  45. HADOOP-2344. Enhance the utility for executing shell commands to read the stdout/stderr streams while waiting for the command to finish (to free up the buffers). Also, this patch throws away stderr of the DF utility. @deprecated org.apache.hadoop.fs.ShellCommand for org.apache.hadoop.util.Shell org.apache.hadoop.util.ShellUtil for org.apache.hadoop.util.Shell.ShellCommandExecutor
      (Amar Kamat via acmurthy)
  46. HADOOP-2511. Fix a javadoc warning in org.apache.hadoop.util.Shell introduced by HADOOP-2344.
      (acmurthy)
  47. HADOOP-2442. Fix TestLocalFileSystemPermission.testLocalFSsetOwner to work on more platforms.
      (Raghu Angadi via nigel)
  48. HADOOP-2488. Fix a regression in random read performance.
      (Michael Stack via rangadi)
  49. HADOOP-2523. Fix TestDFSShell.testFilePermissions on Windows.
      (Raghu Angadi via nigel)
  50. HADOOP-2535. Removed support for deprecated mapred.child.heap.size and fixed some indentation issues in TaskRunner. (acmurthy) Configuration changes to hadoop-default.xml: remove mapred.child.heap.size
  51. HADOOP-2512. Fix error stream handling in Shell. Use exit code to detect shell command errors in RawLocalFileSystem.
      (Raghu Angadi)
  52. HADOOP-2446. Fixes TestHDFSServerPorts and TestMRServerPorts so they do not rely on statically configured ports and cleanup better.
      (nigel)
  53. HADOOP-2537. Make build process compatible with Ant 1.7.0.
      (Hrishikesh via nigel)
  54. HADOOP-1281. Ensure running tasks of completed map TIPs (e.g. speculative tasks) are killed as soon as the TIP completed.
      (acmurthy)
  55. HADOOP-2571. Suppress a suprious warning in test code.
      (cdouglas)
  56. HADOOP-2481. NNBench report its progress periodically.
      (Hairong Kuang via dhruba)
  57. HADOOP-2601. Start name-node on a free port for TestNNThroughputBenchmark.
      (Konstantin Shvachko)
  58. HADOOP-2494. Set +x on contrib/*/bin/* in packaged tar bundle.
      (stack via tomwhite)
  59. HADOOP-2605. Remove bogus leading slash in task-tracker report bindAddress.
      (Konstantin Shvachko)
  60. HADOOP-2620. Trivial. 'bin/hadoop fs -help' did not list chmod, chown, and chgrp.
      (Raghu Angadi)
  61. HADOOP-2614. The DFS WebUI accesses are configured to be from the user specified by dfs.web.ugi. (Tsz Wo (Nicholas), SZE via dhruba)
  62. HADOOP-2543. Implement a "no-permission-checking" mode for smooth upgrade from a pre-0.16 install of HDFS.
      (Hairong Kuang via dhruba)
  63. HADOOP-290. A DataNode log message now prints the target of a replication request correctly.
      (dhruba)
  64. HADOOP-2538. Redirect to a warning, if plaintext parameter is true but the filter parameter is not given in TaskLogServlet.
      (Michael Bieniosek via enis)
  65. HADOOP-2582. Prevent 'bin/hadoop fs -copyToLocal' from creating zero-length files when the src does not exist.
      (Lohit Vijayarenu via cdouglas)
  66. HADOOP-2189. Incrementing user counters should count as progress.
      (ddas)
  67. HADOOP-2649. The NameNode periodically computes replication work for the datanodes. The periodicity of this computation is now configurable.
      (dhruba)
  68. HADOOP-2549. Correct disk size computation so that data-nodes could switch to other local drives if current is full.
      (Hairong Kuang via shv)
  69. HADOOP-2633. Fsck should call name-node methods directly rather than through rpc. (Tsz Wo (Nicholas), SZE via shv)
  70. HADOOP-2687. Modify a few log message generated by dfs client to be logged only at INFO level.
      (stack via dhruba)
  71. HADOOP-2402. Fix BlockCompressorStream to ensure it buffers data before sending it down to the compressor so that each write call doesn't compress.
      (Chris Douglas via acmurthy)
  72. HADOOP-2645. The Metrics initialization code does not throw exceptions when servers are restarted by MiniDFSCluster.
      (Sanjay Radia via dhruba)
  73. HADOOP-2691. Fix a race condition that was causing the DFSClient to erroneously remove a good datanode from a pipeline that actually had another datanode that was bad.
      (dhruba)
  74. HADOOP-1195. All code in FSNamesystem checks the return value of getDataNode for null before using it.
      (dhruba)
  75. HADOOP-2640. Fix a bug in MultiFileSplitInputFormat that was always returning 1 split in some circumstances.
      (Enis Soztutar via nigel)
  76. HADOOP-2626. Fix paths with special characters to work correctly with the local filesystem.
      (Thomas Friol via cutting)
  77. HADOOP-2646. Fix SortValidator to work with fully-qualified working directories.
      (Arun C Murthy via nigel)
  78. HADOOP-2092. Added a ping mechanism to the pipes' task to periodically check if the parent Java task is running, and exit if the parent isn't alive and responding.
      (Amareshwari Sri Ramadasu via acmurthy)
  79. HADOOP-2714. TestDecommission failed on windows because the replication request was timing out.
      (dhruba)
  80. HADOOP-2576. Namenode performance degradation over time triggered by large heartbeat interval.
      (Raghu Angadi)
  81. HADOOP-2713. TestDatanodeDeath failed on windows because the replication request was timing out.
      (dhruba)
  82. HADOOP-2639. Fixes a problem to do with incorrect maintenance of values for runningMapTasks/runningReduceTasks.
      (Amar Kamat and Arun Murthy via ddas)
  83. HADOOP-2723. Fixed the check for checking whether to do user task profiling.
      (Amareshwari Sri Ramadasu via omalley)
  84. HADOOP-2734. Link forrest docs to new http://hadoop.apache.org
      (Doug Cutting via nigel)
  85. HADOOP-2641. Added Apache license headers to 95 files.
      (nigel)
  86. HADOOP-2732. Fix bug in path globbing.
      (Hairong Kuang via nigel)
  87. HADOOP-2404. Fix backwards compatability with hadoop-0.15 configuration files that was broken by HADOOP-2185.
      (omalley)
  88. HADOOP-2755. Fix fsck performance degradation because of permissions issue. (Tsz Wo (Nicholas), SZE via dhruba)
  89. HADOOP-2768. Fix performance regression caused by HADOOP-1707.
      (dhruba borthakur via nigel)
  90. HADOOP-3108. Fix NPE in setPermission and setOwner.
      (shv)

### Release 0.15.3 - 2008-01-18

- BUG FIXES (4)
  1. HADOOP-2562. globPaths supports {ab,cd}.
     (Hairong Kuang via dhruba)
  2. HADOOP-2540. fsck reports missing blocks incorrectly.
     (dhruba)
  3. HADOOP-2570. "work" directory created unconditionally, and symlinks created from the task cwds.
  4. HADOOP-2574. Fixed mapred_tutorial.xml to correct minor errors with the WordCount examples.
     (acmurthy)

### Release 0.15.2 - 2008-01-02

- BUG FIXES (11)
  1. HADOOP-2246. Moved the changelog for HADOOP-1851 from the NEW FEATURES section to the INCOMPATIBLE CHANGES section.
     (acmurthy)
  2. HADOOP-2238. Fix TaskGraphServlet so that it sets the content type of the response appropriately.
     (Paul Saab via enis)
  3. HADOOP-2129. Fix so that distcp works correctly when source is HDFS but not the default filesystem. HDFS paths returned by the listStatus() method are now fully-qualified.
     (cutting)
  4. HADOOP-2378. Fixes a problem where the last task completion event would get created after the job completes.
     (Alejandro Abdelnur via ddas)
  5. HADOOP-2228. Checks whether a job with a certain jobId is already running and then tries to create the JobInProgress object.
     (Johan Oskarsson via ddas)
  6. HADOOP-2422. dfs -cat multiple files fail with 'Unable to write to output stream'.
     (Raghu Angadi via dhruba)
  7. HADOOP-2460. When the namenode encounters ioerrors on writing a transaction log, it stops writing new transactions to that one.
     (Raghu Angadi via dhruba)
  8. HADOOP-2227. Use the LocalDirAllocator uniformly for handling all of the temporary storage required for a given task. It also implies that mapred.local.dir.minspacestart is handled by checking if there is enough free-space on any one of the available disks.
     (Amareshwari Sri Ramadasu via acmurthy)
  9. HADOOP-2437. Fix the LocalDirAllocator to choose the seed for the round-robin disk selections randomly. This helps in spreading data across multiple partitions much better.
     (acmurhty)
  10. HADOOP-2486. When the list of files from the InMemoryFileSystem is obtained for merging, this patch will ensure that only those files whose checksums have also got created (renamed) are returned.
      (ddas)
  11. HADOOP-2456. Hardcode English locale to prevent NumberFormatException from occurring when starting the NameNode with certain locales.
      (Matthias Friedrich via nigel)
- IMPROVEMENTS (4)
  1. HADOOP-2160. Remove project-level, non-user documentation from releases, since it's now maintained in a separate tree.
     (cutting)
  2. HADOOP-1327. Add user documentation for streaming.
     (cutting)
  3. HADOOP-2382. Add hadoop-default.html to subversion.
     (cutting)
  4. HADOOP-2158. hdfsListDirectory calls FileSystem.listStatus instead of FileSystem.listPaths. This reduces the number of RPC calls on the namenode, thereby improving scalability.
     (Christian Kunz via dhruba)

### Release 0.15.1 - 2007-11-27

- INCOMPATIBLE CHANGES (1)
  1. HADOOP-713. Reduce CPU usage on namenode while listing directories. FileSystem.listPaths does not return the size of the entire subtree. Introduced a new API ClientProtocol.getContentLength that returns the size of the subtree.
     (Dhruba Borthakur via dhruba)
- IMPROVEMENTS (1)
  1. HADOOP-1917. Addition of guides/tutorial for better overall documentation for Hadoop. Specifically: * quickstart.html is targetted towards first-time users and helps them setup a single-node cluster and play with Hadoop. * cluster_setup.html helps admins to configure and setup non-trivial hadoop clusters. * mapred_tutorial.html is a comprehensive Map-Reduce tutorial.
     (acmurthy)
- BUG FIXES (3)
  1. HADOOP-2174. Removed the unnecessary Reporter.setStatus call from FSCopyFilesMapper.close which led to a NPE since the reporter isn't valid in the close method.
     (Chris Douglas via acmurthy)
  2. HADOOP-2172. Restore performance of random access to local files by caching positions of local input streams, avoiding a system call.
     (cutting)
  3. HADOOP-2205. Regenerate the Hadoop website since some of the changes made by HADOOP-1917 weren't correctly copied over to the trunk/docs directory. Also fixed a couple of minor typos and broken links.
     (acmurthy)

### Release 0.15.0 - 2007-11-2

- INCOMPATIBLE CHANGES (10)
  1. HADOOP-1708. Make files appear in namespace as soon as they are created.
     (Dhruba Borthakur via dhruba)
  2. HADOOP-999. A HDFS Client immediately informs the NameNode of a new file creation. ClientProtocol version changed from 14 to 15. (Tsz Wo (Nicholas), SZE via dhruba)
  3. HADOOP-932. File locking interfaces and implementations (that were earlier deprecated) are removed. Client Protocol version changed from 15 to 16.
     (Raghu Angadi via dhruba)
  4. HADOOP-1621. FileStatus is now a concrete class and FileSystem.listPaths is deprecated and replaced with listStatus.
     (Chris Douglas via omalley)
  5. HADOOP-1656. The blockSize of a file is stored persistently in the file inode.
     (Dhruba Borthakur via dhruba)
  6. HADOOP-1838. The blocksize of files created with an earlier release is set to the default block size.
     (Dhruba Borthakur via dhruba)
  7. HADOOP-785. Add support for 'final' Configuration parameters, removing support for 'mapred-default.xml', and changing 'hadoop-site.xml' to not override other files. Now folks should generally use 'hadoop-site.xml' for all configurations. Values with a 'final' tag may not be overridden by subsequently loaded configuration files, e.g., by jobs.
     (Arun C. Murthy via cutting)
  8. HADOOP-1846. DatanodeReport in ClientProtocol can report live datanodes, dead datanodes or all datanodes. Client Protocol version changed from 17 to 18.
     (Hairong Kuang via dhruba)
  9. HADOOP-1851. Permit specification of map output compression type and codec, independent of the final output's compression parameters.
     (Arun C Murthy via cutting)
  10. HADOOP-1819. Jobtracker cleanups, including binding ports before clearing state directories, so that inadvertently starting a second jobtracker doesn't trash one that's already running. Removed method JobTracker.getTracker() because the static variable, which stored the value caused initialization problems.
      (omalley via cutting)
- NEW FEATURES (14)
  1. HADOOP-89. A client can access file data even before the creator has closed the file. Introduce a new command "tail" from dfs shell.
     (Dhruba Borthakur via dhruba)
  2. HADOOP-1636. Allow configuration of the number of jobs kept in memory by the JobTracker.
     (Michael Bieniosek via omalley)
  3. HADOOP-1667. Reorganize CHANGES.txt into sections to make it easier to read. Also remove numbering, to make merging easier.
     (cutting)
  4. HADOOP-1610. Add metrics for failed tasks.
     (Devaraj Das via tomwhite)
  5. HADOOP-1767. Add "bin/hadoop job -list" sub-command.
     (taton via cutting)
  6. HADOOP-1351. Add "bin/hadoop job [-fail-task|-kill-task]" sub-commands to terminate a particular task-attempt.
     (Enis Soztutar via acmurthy)
  7. HADOOP-1880. SleepJob : An example job that sleeps at each map and reduce task.
     (enis)
  8. HADOOP-1809. Add a link in web site to #hadoop IRC channel.
     (enis)
  9. HADOOP-1894. Add percentage graphs and mapred task completion graphs to Web User Interface. Users not using Firefox may install a plugin to their browsers to see svg graphics.
     (enis)
  10. HADOOP-1914. Introduce a new NamenodeProtocol to allow secondary namenodes and rebalancing processes to communicate with a primary namenode.
      (Hairong Kuang via dhruba)
  11. HADOOP-1963. Add a FileSystem implementation for the Kosmos Filesystem (KFS).
      (Sriram Rao via cutting)
  12. HADOOP-1822. Allow the specialization and configuration of socket factories. Provide a StandardSocketFactory, and a SocksSocketFactory to allow the use of SOCKS proxies. (taton).
  13. HADOOP-1968. FileSystem supports wildcard input syntax "{ }".
      (Hairong Kuang via dhruba)
  14. HADOOP-2566. Add globStatus method to the FileSystem interface and deprecate globPath and listPath.
      (Hairong Kuang via hairong)
- OPTIMIZATIONS (8)
  1. HADOOP-1910. Reduce the number of RPCs that DistributedFileSystem.create() makes to the namenode.
     (Raghu Angadi via dhruba)
  2. HADOOP-1565. Reduce memory usage of NameNode by replacing TreeMap in HDFS Namespace with ArrayList.
     (Dhruba Borthakur via dhruba)
  3. HADOOP-1743. Change DFS INode from a nested class to standalone class, with specialized subclasses for directories and files, to save memory on the namenode.
     (Konstantin Shvachko via cutting)
  4. HADOOP-1759. Change file name in INode from String to byte[], saving memory on the namenode.
     (Konstantin Shvachko via cutting)
  5. HADOOP-1766. Save memory in namenode by having BlockInfo extend Block, and replace many uses of Block with BlockInfo.
     (Konstantin Shvachko via cutting)
  6. HADOOP-1687. Save memory in namenode by optimizing BlockMap representation.
     (Konstantin Shvachko via cutting)
  7. HADOOP-1774. Remove use of INode.parent in Block CRC upgrade.
     (Raghu Angadi via dhruba)
  8. HADOOP-1788. Increase the buffer size on the Pipes command socket.
     (Amareshwari Sri Ramadasu and Christian Kunz via omalley)
- BUG FIXES (64)
  1. HADOOP-1946. The Datanode code does not need to invoke du on every heartbeat.
     (Hairong Kuang via dhruba)
  2. HADOOP-1935. Fix a NullPointerException in internalReleaseCreate.
     (Dhruba Borthakur)
  3. HADOOP-1933. The nodes listed in include and exclude files are always listed in the datanode report.
     (Raghu Angadi via dhruba)
  4. HADOOP-1953. The job tracker should wait beteween calls to try and delete the system directory
     (Owen O'Malley via devaraj)
  5. HADOOP-1932. TestFileCreation fails with message saying filestatus.dat is of incorrect size.
     (Dhruba Borthakur via dhruba)
  6. HADOOP-1573. Support for 0 reducers in PIPES.
     (Owen O'Malley via devaraj)
  7. HADOOP-1500. Fix typographical errors in the DFS WebUI.
     (Nigel Daley via dhruba)
  8. HADOOP-1076. Periodic checkpoint can continue even if an earlier checkpoint encountered an error.
     (Dhruba Borthakur via dhruba)
  9. HADOOP-1887. The Namenode encounters an ArrayIndexOutOfBoundsException while listing a directory that had a file that was being actively written to.
     (Dhruba Borthakur via dhruba)
  10. HADOOP-1904. The Namenode encounters an exception because the list of blocks per datanode-descriptor was corrupted.
      (Konstantin Shvachko via dhruba)
  11. HADOOP-1762. The Namenode fsimage does not contain a list of Datanodes.
      (Raghu Angadi via dhruba)
  12. HADOOP-1890. Removed debugging prints introduced by HADOOP-1774.
      (Raghu Angadi via dhruba)
  13. HADOOP-1763. Too many lost task trackers on large clusters due to insufficient number of RPC handler threads on the JobTracker.
      (Devaraj Das)
  14. HADOOP-1463. HDFS report correct usage statistics for disk space used by HDFS.
      (Hairong Kuang via dhruba)
  15. HADOOP-1692. In DFS ant task, don't cache the Configuration.
      (Chris Douglas via cutting)
  16. HADOOP-1726. Remove lib/jetty-ext/ant.jar.
      (omalley)
  17. HADOOP-1772. Fix hadoop-daemon.sh script to get correct hostname under Cygwin. (Tsz Wo (Nicholas), SZE via cutting)
  18. HADOOP-1749. Change TestDFSUpgrade to sort files, fixing sporadic test failures.
      (Enis Soztutar via cutting)
  19. HADOOP-1748. Fix tasktracker to be able to launch tasks when log directory is relative.
      (omalley via cutting)
  20. HADOOP-1775. Fix a NullPointerException and an IllegalArgumentException in MapWritable.
      (Jim Kellerman via cutting)
  21. HADOOP-1795. Fix so that jobs can generate output file names with special characters.
      (Fr??d??ric Bertin via cutting)
  22. HADOOP-1810. Fix incorrect value type in MRBench (SmallJobs)
      (Devaraj Das via tomwhite)
  23. HADOOP-1806. Fix ant task to compile again, also fix default builds to compile ant tasks.
      (Chris Douglas via cutting)
  24. HADOOP-1758. Fix escape processing in librecordio to not be quadratic.
      (Vivek Ratan via cutting)
  25. HADOOP-1817. Fix MultiFileSplit to read and write the split length, so that it is not always zero in map tasks.
      (Thomas Friol via cutting)
  26. HADOOP-1853. Fix contrib/streaming to accept multiple -cacheFile options.
      (Prachi Gupta via cutting)
  27. HADOOP-1818. Fix MultiFileInputFormat so that it does not return empty splits when numPaths < numSplits.
      (Thomas Friol via enis)
  28. HADOOP-1840. Fix race condition which leads to task's diagnostic messages getting lost.
      (acmurthy)
  29. HADOOP-1885. Fix race condition in MiniDFSCluster shutdown.
      (Chris Douglas via nigel)
  30. HADOOP-1889. Fix path in EC2 scripts for building your own AMI.
      (tomwhite)
  31. HADOOP-1892. Fix a NullPointerException in the JobTracker when trying to fetch a task's diagnostic messages from the JobClient.
      (Amar Kamat via acmurthy)
  32. HADOOP-1897. Completely remove about.html page from the web site.
      (enis)
  33. HADOOP-1907. Fix null pointer exception when getting task diagnostics in JobClient.
      (Christian Kunz via omalley)
  34. HADOOP-1882. Remove spurious asterisks from decimal number displays.
      (Raghu Angadi via cutting)
  35. HADOOP-1783. Make S3 FileSystem return Paths fully-qualified with scheme and host.
      (tomwhite)
  36. HADOOP-1925. Make pipes' autoconf script look for libsocket and libnsl, so that it can compile under Solaris.
      (omalley)
  37. HADOOP-1940. TestDFSUpgradeFromImage must shut down its MiniDFSCluster.
      (Chris Douglas via nigel)
  38. HADOOP-1930. Fix the blame for failed fetchs on the right host.
      (Arun C. Murthy via omalley)
  39. HADOOP-1934. Fix the platform name on Mac to use underscores rather than spaces.
      (omalley)
  40. HADOOP-1959. Use "/" instead of File.separator in the StatusHttpServer.
      (jimk via omalley)
  41. HADOOP-1626. Improve dfsadmin help messages.
      (Lohit Vijayarenu via dhruba)
  42. HADOOP-1695. The SecondaryNamenode waits for the Primary NameNode to start up.
      (Dhruba Borthakur)
  43. HADOOP-1983. Have Pipes flush the command socket when progress is sent to prevent timeouts during long computations.
      (omalley)
  44. HADOOP-1875. Non-existant directories or read-only directories are filtered from dfs.client.buffer.dir.
      (Hairong Kuang via dhruba)
  45. HADOOP-1992. Fix the performance degradation in the sort validator.
      (acmurthy via omalley)
  46. HADOOP-1874. Move task-outputs' promotion/discard to a separate thread distinct from the main heartbeat-processing thread. The main upside being that we do not lock-up the JobTracker during HDFS operations, which otherwise may lead to lost tasktrackers if the NameNode is unresponsive.
      (Devaraj Das via acmurthy)
  47. HADOOP-2026. Namenode prints out one log line for "Number of transactions" at most once every minute.
      (Dhruba Borthakur)
  48. HADOOP-2022. Ensure that status information for successful tasks is correctly recorded at the JobTracker, so that, for example, one may view correct information via taskdetails.jsp. This bug was introduced by HADOOP-1874.
      (Amar Kamat via acmurthy)
  49. HADOOP-2031. Correctly maintain the taskid which takes the TIP to completion, failing which the case of lost tasktrackers isn't handled properly i.e. the map TIP is incorrectly left marked as 'complete' and it is never rescheduled elsewhere, leading to hung reduces.
      (Devaraj Das via acmurthy)
  50. HADOOP-2018. The source datanode of a data transfer waits for a response from the target datanode before closing the data stream.
      (Hairong Kuang via dhruba)
  51. HADOOP-2023. Disable TestLocalDirAllocator on Windows.
      (Hairong Kuang via nigel)
  52. HADOOP-2016. Ignore status-updates from FAILED/KILLED tasks at the TaskTracker. This fixes a race-condition which caused the tasks to wrongly remain in the RUNNING state even after being killed by the JobTracker and thus handicap the cleanup of the task's output sub-directory.
      (acmurthy)
  53. HADOOP-1771. Fix a NullPointerException in streaming caused by an IOException in MROutputThread.
      (lohit vijayarenu via nigel)
  54. HADOOP-2028. Fix distcp so that the log dir does not need to be specified and the destination does not need to exist.
      (Chris Douglas via nigel)
  55. HADOOP-2044. The namenode protects all lease manipulations using a sortedLease lock.
      (Dhruba Borthakur)
  56. HADOOP-2051. The TaskCommit thread should not die for exceptions other than the InterruptedException. This behavior is there for the other long running threads in the JobTracker.
      (Arun C Murthy via ddas)
  57. HADOOP-1973. The FileSystem object would be accessed on the JobTracker through a RPC in the InterTrackerProtocol. The check for the object being null was missing and hence NPE would be thrown sometimes. This issue fixes that problem.
      (Amareshwari Sri Ramadasu via ddas)
  58. HADOOP-2033. The SequenceFile.Writer.sync method was a no-op, which caused very uneven splits for applications like distcp that count on them.
      (omalley)
  59. HADOOP-2070. Added a flush method to pipes' DownwardProtocol and call that before waiting for the application to finish to ensure all buffered data is flushed.
      (Owen O'Malley via acmurthy)
  60. HADOOP-2080. Fixed calculation of the checksum file size when the values are large.
      (omalley)
  61. HADOOP-2048. Change error handling in distcp so that each map copies as much as possible before reporting the error. Also report progress on every copy.
      (Chris Douglas via omalley)
  62. HADOOP-2073. Change size of VERSION file after writing contents to it.
      (Konstantin Shvachko via dhruba)
  63. HADOOP-2102. Fix the deprecated ToolBase to pass its Configuration object to the superceding ToolRunner to ensure it picks up the appropriate configuration resources.
      (Dennis Kubes and Enis Soztutar via acmurthy)
  64. HADOOP-2103. Fix minor javadoc bugs introduce by HADOOP-2046.
      (Nigel Daley via acmurthy)
- IMPROVEMENTS (37)
  1. HADOOP-1908. Restructure data node code so that block sending and receiving are seperated from data transfer header handling.
     (Hairong Kuang via dhruba)
  2. HADOOP-1921. Save the configuration of completed/failed jobs and make them available via the web-ui.
     (Amar Kamat via devaraj)
  3. HADOOP-1266. Remove dependency of package org.apache.hadoop.net on org.apache.hadoop.dfs.
     (Hairong Kuang via dhruba)
  4. HADOOP-1779. Replace INodeDirectory.getINode() by a getExistingPathINodes() to allow the retrieval of all existing INodes along a given path in a single lookup. This facilitates removal of the 'parent' field in the inode.
     (Christophe Taton via dhruba)
  5. HADOOP-1756. Add toString() to some Writable-s.
     (ab)
  6. HADOOP-1727. New classes: MapWritable and SortedMapWritable.
     (Jim Kellerman via ab)
  7. HADOOP-1651. Improve progress reporting.
     (Devaraj Das via tomwhite)
  8. HADOOP-1595. dfsshell can wait for a file to achieve its intended replication target. (Tsz Wo (Nicholas), SZE via dhruba)
  9. HADOOP-1693. Remove un-needed log fields in DFS replication classes, since the log may be accessed statically.
     (Konstantin Shvachko via cutting)
  10. HADOOP-1231. Add generics to Mapper and Reducer interfaces.
      (tomwhite via cutting)
  11. HADOOP-1436. Improved command-line APIs, so that all tools need not subclass ToolBase, and generic parameter parser is public.
      (Enis Soztutar via cutting)
  12. HADOOP-1703. DFS-internal code cleanups, removing several uses of the obsolete UTF8.
      (Christophe Taton via cutting)
  13. HADOOP-1731. Add Hadoop's version to contrib jar file names.
      (cutting)
  14. HADOOP-1689. Make shell scripts more portable. All shell scripts now explicitly depend on bash, but do not require that bash be installed in a particular location, as long as it is on $PATH.
      (cutting)
  15. HADOOP-1744. Remove many uses of the deprecated UTF8 class from the HDFS namenode.
      (Christophe Taton via cutting)
  16. HADOOP-1654. Add IOUtils class, containing generic io-related utility methods.
      (Enis Soztutar via cutting)
  17. HADOOP-1158. Change JobTracker to record map-output transmission errors and use them to trigger speculative re-execution of tasks.
      (Arun C Murthy via cutting)
  18. HADOOP-1601. Change GenericWritable to use ReflectionUtils for instance creation, avoiding classloader issues, and to implement Configurable.
      (Enis Soztutar via cutting)
  19. HADOOP-1750. Log standard output and standard error when forking task processes.
      (omalley via cutting)
  20. HADOOP-1803. Generalize build.xml to make files in all src/contrib/*/bin directories executable.
      (stack via cutting)
  21. HADOOP-1739. Let OS always choose the tasktracker's umbilical port. Also switch default address for umbilical connections to loopback.
      (cutting)
  22. HADOOP-1812. Let OS choose ports for IPC and RPC unit tests.
      (cutting)
  23. HADOOP-1825. Create $HADOOP_PID_DIR when it does not exist.
      (Michael Bieniosek via cutting)
  24. HADOOP-1425. Replace uses of ToolBase with the Tool interface.
      (Enis Soztutar via cutting)
  25. HADOOP-1569. Reimplement DistCP to use the standard FileSystem/URI code in Hadoop so that you can copy from and to all of the supported file systems.
      (Chris Douglas via omalley)
  26. HADOOP-1018. Improve documentation w.r.t handling of lost hearbeats between TaskTrackers and JobTracker.
      (acmurthy)
  27. HADOOP-1718. Add ant targets for measuring code coverage with clover.
      (simonwillnauer via nigel)
  28. HADOOP-1592. Log error messages to the client console when tasks fail.
      (Amar Kamat via cutting)
  29. HADOOP-1879. Remove some unneeded casts.
      (Nilay Vaish via cutting)
  30. HADOOP-1878. Add space between priority links on job details page.
      (Thomas Friol via cutting)
  31. HADOOP-120. In ArrayWritable, prevent creation with null value class, and improve documentation.
      (Cameron Pope via cutting)
  32. HADOOP-1926. Add a random text writer example/benchmark so that we can benchmark compression codecs on random data.
      (acmurthy via omalley)
  33. HADOOP-1906. Warn the user if they have an obsolete madred-default.xml file in their configuration directory.
      (acmurthy via omalley)
  34. HADOOP-1971. Warn when job does not specify a jar.
      (enis via cutting)
  35. HADOOP-1942. Increase the concurrency of transaction logging to edits log. Reduce the number of syncs by double-buffering the changes to the transaction log.
      (Dhruba Borthakur)
  36. HADOOP-2046. Improve mapred javadoc.
      (Arun C. Murthy via cutting)
  37. HADOOP-2105. Improve overview.html to clarify supported platforms, software pre-requisites for hadoop, how to install them on various platforms and a better general description of hadoop and it's utility.
      (Jim Kellerman via acmurthy)

### Release 0.14.4 - 2007-11-26

- BUG FIXES (3)
  1. HADOOP-2140. Add missing Apache Licensing text at the front of several C and C++ files.
  2. HADOOP-2169. Fix the DT_SONAME field of libhdfs.so to set it to the correct value of 'libhdfs.so', currently it is set to the absolute path of libhdfs.so.
     (acmurthy)
  3. HADOOP-2001. Make the job priority updates and job kills synchronized on the JobTracker. Deadlock was seen in the JobTracker because of the lack of this synchronization.
     (Arun C Murthy via ddas)

### Release 0.14.3 - 2007-10-19

- BUG FIXES (3)
  1. HADOOP-2053. Fixed a dangling reference to a memory buffer in the map output sorter.
     (acmurthy via omalley)
  2. HADOOP-2036. Fix a NullPointerException in JvmMetrics class.
     (nigel)
  3. HADOOP-2043. Release 0.14.2 was compiled with Java 1.6 rather than Java 1.5.
     (cutting)

### Release 0.14.2 - 2007-10-09

- BUG FIXES (9)
  1. HADOOP-1948. Removed spurious error message during block crc upgrade.
     (Raghu Angadi via dhruba)
  2. HADOOP-1862. reduces are getting stuck trying to find map outputs.
     (Arun C. Murthy via ddas)
  3. HADOOP-1977. Fixed handling of ToolBase cli options in JobClient.
     (enis via omalley)
  4. HADOOP-1972. Fix LzoCompressor to ensure the user has actually asked to finish compression.
     (arun via omalley)
  5. HADOOP-1970. Fix deadlock in progress reporting in the task.
     (Vivek Ratan via omalley)
  6. HADOOP-1978. Name-node removes edits.new after a successful startup.
     (Konstantin Shvachko via dhruba)
  7. HADOOP-1955. The Namenode tries to not pick the same source Datanode for a replication request if the earlier replication request for the same block and that source Datanode had failed.
     (Raghu Angadi via dhruba)
  8. HADOOP-1961. The -get option to dfs-shell works when a single filename is specified.
     (Raghu Angadi via dhruba)
  9. HADOOP-1997. TestCheckpoint closes the edits file after writing to it, otherwise the rename of this file on Windows fails.
     (Konstantin Shvachko via dhruba)

### Release 0.14.1 - 2007-09-04

- BUG FIXES (3)
  1. HADOOP-1740. Fix null pointer exception in sorting map outputs.
     (Devaraj Das via omalley)
  2. HADOOP-1790. Fix tasktracker to work correctly on multi-homed boxes.
     (Torsten Curdt via cutting)
  3. HADOOP-1798. Fix jobtracker to correctly account for failed tasks.
     (omalley via cutting)

### Release 0.14.0 - 2007-08-17

- INCOMPATIBLE CHANGES (160)
  1. HADOOP-1134. CONFIG/API - dfs.block.size must now be a multiple of io.byte.per.checksum, otherwise new files can not be written. LAYOUT - DFS layout version changed from -6 to -7, which will require an upgrade from previous versions. PROTOCOL - Datanode RPC protocol version changed from 7 to 8.
  2. HADOOP-1283 API - deprecated file locking API.
  3. HADOOP-894 PROTOCOL - changed ClientProtocol to fetch parts of block locations.
  4. HADOOP-1336 CONFIG - Enable speculative execution by default.
  5. HADOOP-1197 API - deprecated method for Configuration.getObject, because Configurations should only contain strings.
  6. HADOOP-1343 API - deprecate Configuration.set(String,Object) so that only strings are put in Configrations.
  7. HADOOP-1207 CLI - Fix FsShell 'rm' command to continue when a non-existent file is encountered.
  8. HADOOP-1473 CLI/API - Job, TIP, and Task id formats have changed and are now unique across job tracker restarts.
  9. HADOOP-1400 API - JobClient constructor now takes a JobConf object instead of a Configuration object.

     NEW FEATURES and BUG FIXES
  10. HADOOP-1197. In Configuration, deprecate getObject() and add getRaw(), which skips variable expansion.
      (omalley via cutting)
  11. HADOOP-1343. In Configuration, deprecate set(String,Object) and implement Iterable.
      (omalley via cutting)
  12. HADOOP-1344. Add RunningJob#getJobName().
      (Michael Bieniosek via cutting)
  13. HADOOP-1342. In aggregators, permit one to limit the number of unique values per key.
      (Runping Qi via cutting)
  14. HADOOP-1340. Set the replication factor of the MD5 file in the filecache to be the same as the replication factor of the original file.
      (Dhruba Borthakur via tomwhite.)
  15. HADOOP-1355. Fix null pointer dereference in TaskLogAppender.append(LoggingEvent).
      (Arun C Murthy via tomwhite.)
  16. HADOOP-1357. Fix CopyFiles to correctly avoid removing "/".
      (Arun C Murthy via cutting)
  17. HADOOP-234. Add pipes facility, which permits writing MapReduce programs in C++.
  18. HADOOP-1359. Fix a potential NullPointerException in HDFS.
      (Hairong Kuang via cutting)
  19. HADOOP-1364. Fix inconsistent synchronization in SequenceFile.
      (omalley via cutting)
  20. HADOOP-1379. Add findbugs target to build.xml.
      (Nigel Daley via cutting)
  21. HADOOP-1364. Fix various inconsistent synchronization issues.
      (Devaraj Das via cutting)
  22. HADOOP-1393. Remove a potential unexpected negative number from uses of random number generator.
      (omalley via cutting)
  23. HADOOP-1387. A number of "performance" code-cleanups suggested by findbugs.
      (Arun C Murthy via cutting)
  24. HADOOP-1401. Add contrib/hbase javadoc to tree.
      (stack via cutting)
  25. HADOOP-894. Change HDFS so that the client only retrieves a limited number of block locations per request from the namenode.
      (Konstantin Shvachko via cutting)
  26. HADOOP-1406. Plug a leak in MapReduce's use of metrics.
      (David Bowen via cutting)
  27. HADOOP-1394. Implement "performance" code-cleanups in HDFS suggested by findbugs.
      (Raghu Angadi via cutting)
  28. HADOOP-1413. Add example program that uses Knuth's dancing links algorithm to solve pentomino problems.
      (omalley via cutting)
  29. HADOOP-1226. Change HDFS so that paths it returns are always fully qualified.
      (Dhruba Borthakur via cutting)
  30. HADOOP-800. Improvements to HDFS web-based file browser.
      (Enis Soztutar via cutting)
  31. HADOOP-1408. Fix a compiler warning by adding a class to replace a generic.
      (omalley via cutting)
  32. HADOOP-1376. Modify RandomWriter example so that it can generate data for the Terasort benchmark.
      (Devaraj Das via cutting)
  33. HADOOP-1429. Stop logging exceptions during normal IPC server shutdown.
      (stack via cutting)
  34. HADOOP-1461. Fix the synchronization of the task tracker to avoid lockups in job cleanup.
      (Arun C Murthy via omalley)
  35. HADOOP-1446. Update the TaskTracker metrics while the task is running.
      (Devaraj via omalley)
  36. HADOOP-1414. Fix a number of issues identified by FindBugs as "Bad Practice".
      (Dhruba Borthakur via cutting)
  37. HADOOP-1392. Fix "correctness" bugs identified by FindBugs in fs and dfs packages.
      (Raghu Angadi via cutting)
  38. HADOOP-1412. Fix "dodgy" bugs identified by FindBugs in fs and io packages.
      (Hairong Kuang via cutting)
  39. HADOOP-1261. Remove redundant events from HDFS namenode's edit log when a datanode restarts.
      (Raghu Angadi via cutting)
  40. HADOOP-1336. Re-enable speculative execution by default.
      (omalley via cutting)
  41. HADOOP-1311. Fix a bug in BytesWritable#set() where start offset was ignored.
      (Dhruba Borthakur via cutting)
  42. HADOOP-1450. Move checksumming closer to user code, so that checksums are created before data is stored in large buffers and verified after data is read from large buffers, to better catch memory errors.
      (cutting)
  43. HADOOP-1447. Add support in contrib/data_join for text inputs.
      (Senthil Subramanian via cutting)
  44. HADOOP-1456. Fix TestDecommission assertion failure by setting the namenode to ignore the load on datanodes while allocating replicas.
      (Dhruba Borthakur via tomwhite)
  45. HADOOP-1396. Fix FileNotFoundException on DFS block.
      (Dhruba Borthakur via tomwhite)
  46. HADOOP-1467. Remove redundant counters from WordCount example.
      (Owen O'Malley via tomwhite)
  47. HADOOP-1139. Log HDFS block transitions at INFO level, to better enable diagnosis of problems.
      (Dhruba Borthakur via cutting)
  48. HADOOP-1269. Finer grained locking in HDFS namenode.
      (Dhruba Borthakur via cutting)
  49. HADOOP-1438. Improve HDFS documentation, correcting typos and making images appear in PDF. Also update copyright date for all docs.
      (Luke Nezda via cutting)
  50. HADOOP-1457. Add counters for monitoring task assignments.
      (Arun C Murthy via tomwhite)
  51. HADOOP-1472. Fix so that timed-out tasks are counted as failures rather than as killed.
      (Arun C Murthy via cutting)
  52. HADOOP-1234. Fix a race condition in file cache that caused tasktracker to not be able to find cached files.
      (Arun C Murthy via cutting)
  53. HADOOP-1482. Fix secondary namenode to roll info port.
      (Dhruba Borthakur via cutting)
  54. HADOOP-1300. Improve removal of excess block replicas to be rack-aware. Attempts are now made to keep replicas on more racks.
      (Hairong Kuang via cutting)
  55. HADOOP-1417. Disable a few FindBugs checks that generate a lot of spurious warnings.
      (Nigel Daley via cutting)
  56. HADOOP-1320. Rewrite RandomWriter example to bypass reduce.
      (Arun C Murthy via cutting)
  57. HADOOP-1449. Add some examples to contrib/data_join.
      (Senthil Subramanian via cutting)
  58. HADOOP-1459. Fix so that, in HDFS, getFileCacheHints() returns hostnames instead of IP addresses.
      (Dhruba Borthakur via cutting)
  59. HADOOP-1493. Permit specification of "java.library.path" system property in "mapred.child.java.opts" configuration property.
      (Enis Soztutar via cutting)
  60. HADOOP-1372. Use LocalDirAllocator for HDFS temporary block files, so that disk space, writability, etc. is considered.
      (Dhruba Borthakur via cutting)
  61. HADOOP-1193. Pool allocation of compression codecs. This eliminates a memory leak that could cause OutOfMemoryException, and also substantially improves performance.
      (Arun C Murthy via cutting)
  62. HADOOP-1492. Fix a NullPointerException handling version mismatch during datanode registration.
      (Konstantin Shvachko via cutting)
  63. HADOOP-1442. Fix handling of zero-length input splits.
      (Senthil Subramanian via cutting)
  64. HADOOP-1444. Fix HDFS block id generation to check pending blocks for duplicates.
      (Dhruba Borthakur via cutting)
  65. HADOOP-1207. Fix FsShell's 'rm' command to not stop when one of the named files does not exist.
      (Tsz Wo Sze via cutting)
  66. HADOOP-1475. Clear tasktracker's file cache before it re-initializes, to avoid confusion.
      (omalley via cutting)
  67. HADOOP-1505. Remove spurious stacktrace in ZlibFactory introduced in HADOOP-1093.
      (Michael Stack via tomwhite)
  68. HADOOP-1484. Permit one to kill jobs from the web ui. Note that this is disabled by default. One must set "webinterface.private.actions" to enable this.
      (Enis Soztutar via cutting)
  69. HADOOP-1003. Remove flushing of namenode edit log from primary namenode lock, increasing namenode throughput.
      (Dhruba Borthakur via cutting)
  70. HADOOP-1023. Add links to searchable mail archives.
      (tomwhite via cutting)
  71. HADOOP-1504. Fix terminate-hadoop-cluster script in contrib/ec2 to only terminate Hadoop instances, and not other instances started by the same user.
      (tomwhite via cutting)
  72. HADOOP-1462. Improve task progress reporting. Progress reports are no longer blocking since i/o is performed in a separate thread. Reporting during sorting and more is also more consistent.
      (Vivek Ratan via cutting)
  73. [ intentionally blank ]
  74. HADOOP-1453. Remove some unneeded calls to FileSystem#exists() when opening files, reducing the namenode load somewhat.
      (Raghu Angadi via cutting)
  75. HADOOP-1489. Fix text input truncation bug due to mark/reset. Add a unittest.
      (Bwolen Yang via cutting)
  76. HADOOP-1455. Permit specification of arbitrary job options on pipes command line.
      (Devaraj Das via cutting)
  77. HADOOP-1501. Better randomize sending of block reports to namenode, so reduce load spikes.
      (Dhruba Borthakur via cutting)
  78. HADOOP-1147. Remove @author tags from Java source files.
  79. HADOOP-1283. Convert most uses of UTF8 in the namenode to be String.
      (Konstantin Shvachko via cutting)
  80. HADOOP-1511. Speedup hbase unit tests.
      (stack via cutting)
  81. HADOOP-1517. Remove some synchronization in namenode to permit finer grained locking previously added.
      (Konstantin Shvachko via cutting)
  82. HADOOP-1512. Fix failing TestTextInputFormat on Windows.
      (Senthil Subramanian via nigel)
  83. HADOOP-1518. Add a session id to job metrics, for use by HOD.
      (David Bowen via cutting)
  84. HADOOP-1292. Change 'bin/hadoop fs -get' to first copy files to a temporary name, then rename them to their final name, so that failures don't leave partial files.
      (Tsz Wo Sze via cutting)
  85. HADOOP-1377. Add support for modification time to FileSystem and implement in HDFS and local implementations. Also, alter access to file properties to be through a new FileStatus interface.
      (Dhruba Borthakur via cutting)
  86. HADOOP-1515. Add MultiFileInputFormat, which can pack multiple, typically small, input files into each split.
      (Enis Soztutar via cutting)
  87. HADOOP-1514. Make reducers report progress while waiting for map outputs, so they're not killed.
      (Vivek Ratan via cutting)
  88. HADOOP-1508. Add an Ant task for FsShell operations. Also add new FsShell commands "touchz", "test" and "stat".
      (Chris Douglas via cutting)
  89. HADOOP-1028. Add log messages for server startup and shutdown.
      (Tsz Wo Sze via cutting)
  90. HADOOP-1485. Add metrics for monitoring shuffle.
      (Devaraj Das via cutting)
  91. HADOOP-1536. Remove file locks from libhdfs tests.
      (Dhruba Borthakur via nigel)
  92. HADOOP-1520. Add appropriate synchronization to FSEditsLog.
      (Dhruba Borthakur via nigel)
  93. HADOOP-1513. Fix a race condition in directory creation.
      (Devaraj via omalley)
  94. HADOOP-1546. Remove spurious column from HDFS web UI.
      (Dhruba Borthakur via cutting)
  95. HADOOP-1556. Make LocalJobRunner delete working files at end of job run.
      (Devaraj Das via tomwhite)
  96. HADOOP-1571. Add contrib lib directories to root build.xml javadoc classpath.
      (Michael Stack via tomwhite)
  97. HADOOP-1554. Log killed tasks to the job history and display them on the web/ui.
      (Devaraj Das via omalley)
  98. HADOOP-1533. Add persistent error logging for distcp. The logs are stored into a specified hdfs directory.
      (Senthil Subramanian via omalley)
  99. HADOOP-1286. Add support to HDFS for distributed upgrades, which permits coordinated upgrade of datanode data.
      (Konstantin Shvachko via cutting)
  100. HADOOP-1580. Improve contrib/streaming so that subprocess exit status is displayed for errors.
       (John Heidemann via cutting)
  101. HADOOP-1448. In HDFS, randomize lists of non-local block locations returned to client, so that load is better balanced.
       (Hairong Kuang via cutting)
  102. HADOOP-1578. Fix datanode to send its storage id to namenode during registration.
       (Konstantin Shvachko via cutting)
  103. HADOOP-1584. Fix a bug in GenericWritable which limited it to 128 types instead of 256.
       (Espen Amble Kolstad via cutting)
  104. HADOOP-1473. Make job ids unique across jobtracker restarts.
       (omalley via cutting)
  105. HADOOP-1582. Fix hdfslib to return 0 instead of -1 at end-of-file, per C conventions.
       (Christian Kunz via cutting)
  106. HADOOP-911. Fix a multithreading bug in libhdfs.
       (Christian Kunz)
  107. HADOOP-1486. Fix so that fatal exceptions in namenode cause it to exit.
       (Dhruba Borthakur via cutting)
  108. HADOOP-1470. Factor checksum generation and validation out of ChecksumFileSystem so that it can be reused by FileSystem's with built-in checksumming.
       (Hairong Kuang via cutting)
  109. HADOOP-1590. Use relative urls in jobtracker jsp pages, so that webapp can be used in non-root contexts.
       (Thomas Friol via cutting)
  110. HADOOP-1596. Fix the parsing of taskids by streaming and improve the error reporting.
       (omalley)
  111. HADOOP-1535. Fix the user-controlled grouping to the reduce function.
       (Vivek Ratan via omalley)
  112. HADOOP-1585. Modify GenericWritable to declare the classes as subtypes of Writable
       (Espen Amble Kolstad via omalley)
  113. HADOOP-1576. Fix errors in count of completed tasks when speculative execution is enabled.
       (Arun C Murthy via cutting)
  114. HADOOP-1598. Fix license headers: adding missing; updating old.
       (Enis Soztutar via cutting)
  115. HADOOP-1547. Provide examples for aggregate library.
       (Runping Qi via tomwhite)
  116. HADOOP-1570. Permit jobs to enable and disable the use of hadoop's native library.
       (Arun C Murthy via cutting)
  117. HADOOP-1433. Add job priority.
       (Johan Oskarsson via tomwhite)
  118. HADOOP-1597. Add status reports and post-upgrade options to HDFS distributed upgrade.
       (Konstantin Shvachko via cutting)
  119. HADOOP-1524. Permit user task logs to appear as they're created.
       (Michael Bieniosek via cutting)
  120. HADOOP-1599. Fix distcp bug on Windows.
       (Senthil Subramanian via cutting)
  121. HADOOP-1562. Add JVM metrics, including GC and logging stats.
       (David Bowen via cutting)
  122. HADOOP-1613. Fix "DFS Health" page to display correct time of last contact.
       (Dhruba Borthakur via cutting)
  123. HADOOP-1134. Add optimized checksum support to HDFS. Checksums are now stored with each block, rather than as parallel files. This reduces the namenode's memory requirements and increases data integrity.
       (Raghu Angadi via cutting)
  124. HADOOP-1400. Make JobClient retry requests, so that clients can survive jobtracker problems.
       (omalley via cutting)
  125. HADOOP-1564. Add unit tests for HDFS block-level checksums.
       (Dhruba Borthakur via cutting)
  126. HADOOP-1620. Reduce the number of abstract FileSystem methods, simplifying implementations.
       (cutting)
  127. HADOOP-1625. Fix a "could not move files" exception in datanode.
       (Raghu Angadi via cutting)
  128. HADOOP-1624. Fix an infinite loop in datanode.
       (Raghu Angadi via cutting)
  129. HADOOP-1084. Switch mapred file cache to use file modification time instead of checksum to detect file changes, as checksums are no longer easily accessed.
       (Arun C Murthy via cutting)
  130. HADOOP-1623. Fix an infinite loop when copying directories.
       (Dhruba Borthakur via cutting)
  131. HADOOP-1603. Fix a bug in namenode initialization where default replication is sometimes reset to one on restart.
       (Raghu Angadi via cutting)
  132. HADOOP-1635. Remove hardcoded keypair name and fix launch-hadoop-cluster to support later versions of ec2-api-tools.
       (Stu Hood via tomwhite)
  133. HADOOP-1638. Fix contrib EC2 scripts to support NAT addressing.
       (Stu Hood via tomwhite)
  134. HADOOP-1632. Fix an IllegalArgumentException in fsck.
       (Hairong Kuang via cutting)
  135. HADOOP-1619. Fix FSInputChecker to not attempt to read past EOF.
       (Hairong Kuang via cutting)
  136. HADOOP-1640. Fix TestDecommission on Windows.
       (Dhruba Borthakur via cutting)
  137. HADOOP-1587. Fix TestSymLink to get required system properties.
       (Devaraj Das via omalley)
  138. HADOOP-1628. Add block CRC protocol unit tests.
       (Raghu Angadi via omalley)
  139. HADOOP-1653. FSDirectory code-cleanups. FSDirectory.INode becomes a static class.
       (Christophe Taton via dhruba)
  140. HADOOP-1066. Restructure documentation to make more user friendly.
       (Connie Kleinjans and Jeff Hammerbacher via cutting)
  141. HADOOP-1551. libhdfs supports setting replication factor and retrieving modification time of files.
       (Sameer Paranjpye via dhruba)
  142. HADOOP-1647. FileSystem.getFileStatus returns valid values for "/".
       (Dhruba Borthakur via dhruba)
  143. HADOOP-1657. Fix NNBench to ensure that the block size is a multiple of bytes.per.checksum.
       (Raghu Angadi via dhruba)
  144. HADOOP-1553. Replace user task output and log capture code to use shell redirection instead of copier threads in the TaskTracker. Capping the size of the output is now done via tail in memory and thus should not be large. The output of the tasklog servlet is not forced into UTF8 and is not buffered entirely in memory. (omalley) Configuration changes to hadoop-default.xml: remove mapred.userlog.num.splits remove mapred.userlog.purge.splits change default mapred.userlog.limit.kb to 0 (no limit) change default mapred.userlog.retain.hours to 24 Configuration changes to log4j.properties: remove log4j.appender.TLA.noKeepSplits remove log4j.appender.TLA.purgeLogSplits remove log4j.appender.TLA.logsRetainHours URL changes: http://<tasktracker>/tasklog.jsp -> http://<tasktracker>tasklog with parameters limited to start and end, which may be positive (from start) or negative (from end). Environment: require bash (v2 or later) and tail
  145. HADOOP-1659. Fix a job id/job name mixup.
       (Arun C. Murthy via omalley)
  146. HADOOP-1665. With HDFS Trash enabled and the same file was created and deleted more than once, the suceeding deletions creates Trash item names suffixed with a integer.
       (Dhruba Borthakur via dhruba)
  147. HADOOP-1666. FsShell object can be used for multiple fs commands.
       (Dhruba Borthakur via dhruba)
  148. HADOOP-1654. Remove performance regression introduced by Block CRC.
       (Raghu Angadi via dhruba)
  149. HADOOP-1680. Improvements to Block CRC upgrade messages.
       (Raghu Angadi via dhruba)
  150. HADOOP-71. Allow Text and SequenceFile Map/Reduce inputs from non-default filesystems.
       (omalley)
  151. HADOOP-1568. Expose HDFS as xml/http filesystem to provide cross-version compatability.
       (Chris Douglas via omalley)
  152. HADOOP-1668. Added an INCOMPATIBILITY section to CHANGES.txt.
       (nigel)
  153. HADOOP-1629. Added a upgrade test for HADOOP-1134.
       (Raghu Angadi via nigel)
  154. HADOOP-1698. Fix performance problems on map output sorting for jobs with large numbers of reduces.
       (Devaraj Das via omalley)
  155. HADOOP-1716. Fix a Pipes wordcount example to remove the 'file:' schema from its output path.
       (omalley via cutting)
  156. HADOOP-1714. Fix TestDFSUpgradeFromImage to work on Windows.
       (Raghu Angadi via nigel)
  157. HADOOP-1663. Return a non-zero exit code if streaming fails.
       (Lohit Renu via omalley)
  158. HADOOP-1712. Fix an unhandled exception on datanode during block CRC upgrade.
       (Raghu Angadi via cutting)
  159. HADOOP-1717. Fix TestDFSUpgradeFromImage to work on Solaris.
       (nigel via cutting)
  160. HADOOP-1437. Add Eclipse plugin in contrib.
       (Eugene Hung and Christophe Taton via cutting)

### Release 0.13.0 - 2007-06-08

1. HADOOP-1047. Fix TestReplication to succeed more reliably.
   (Hairong Kuang via cutting)
2. HADOOP-1063. Fix a race condition in MiniDFSCluster test code.
   (Hairong Kuang via cutting)
3. HADOOP-1101. In web ui, split shuffle statistics from reduce statistics, and add some task averages.
   (Devaraj Das via cutting)
4. HADOOP-1071. Improve handling of protocol version mismatch in JobTracker.
   (Tahir Hashmi via cutting)
5. HADOOP-1116. Increase heap size used for contrib unit tests.
   (Philippe Gassmann via cutting)
6. HADOOP-1120. Add contrib/data_join, tools to simplify joining data from multiple sources using MapReduce.
   (Runping Qi via cutting)
7. HADOOP-1064. Reduce log level of some DFSClient messages.
   (Dhruba Borthakur via cutting)
8. HADOOP-1137. Fix StatusHttpServer to work correctly when resources are in a jar file.
   (Benjamin Reed via cutting)
9. HADOOP-1094. Optimize generated Writable implementations for records to not allocate a new BinaryOutputArchive or BinaryInputArchive per call.
   (Milind Bhandarkar via cutting)
10. HADOOP-1068. Improve error message for clusters with 0 datanodes.
    (Dhruba Borthakur via tomwhite)
11. HADOOP-1122. Fix divide-by-zero exception in FSNamesystem chooseTarget method.
    (Dhruba Borthakur via tomwhite)
12. HADOOP-1131. Add a closeAll() static method to FileSystem.
    (Philippe Gassmann via tomwhite)
13. HADOOP-1085. Improve port selection in HDFS and MapReduce test code. Ports are now selected by the OS during testing rather than by probing for free ports, improving test reliability.
    (Arun C Murthy via cutting)
14. HADOOP-1153. Fix HDFS daemons to correctly stop their threads.
    (Konstantin Shvachko via cutting)
15. HADOOP-1146. Add a counter for reduce input keys and rename the "reduce input records" counter to be "reduce input groups".
    (David Bowen via cutting)
16. HADOOP-1165. In records, replace idential generated toString methods with a method on the base class.
    (Milind Bhandarkar via cutting)
17. HADOOP-1164. Fix TestReplicationPolicy to specify port zero, so that a free port is automatically selected.
    (omalley via cutting)
18. HADOOP-1166. Add a NullOutputFormat and use it in the RandomWriter example.
    (omalley via cutting)
19. HADOOP-1169. Fix a cut/paste error in CopyFiles utility so that S3-based source files are correctly copied.
    (Michael Stack via cutting)
20. HADOOP-1167. Remove extra synchronization in InMemoryFileSystem.
    (omalley via cutting)
21. HADOOP-1110. Fix an off-by-one error counting map inputs.
    (David Bowen via cutting)
22. HADOOP-1178. Fix a NullPointerException during namenode startup.
    (Dhruba Borthakur via cutting)
23. HADOOP-1011. Fix a ConcurrentModificationException when viewing job history.
    (Tahir Hashmi via cutting)
24. HADOOP-672. Improve help for fs shell commands.
    (Dhruba Borthakur via cutting)
25. HADOOP-1170. Improve datanode performance by removing device checks from common operations.
    (Igor Bolotin via cutting)
26. HADOOP-1090. Fix SortValidator's detection of whether the input file belongs to the sort-input or sort-output directory.
    (Arun C Murthy via tomwhite)
27. HADOOP-1081. Fix bin/hadoop on Darwin.
    (Michael Bieniosek via cutting)
28. HADOOP-1045. Add contrib/hbase, a BigTable-like online database.
    (Jim Kellerman via cutting)
29. HADOOP-1156. Fix a NullPointerException in MiniDFSCluster.
    (Hairong Kuang via cutting)
30. HADOOP-702. Add tools to help automate HDFS upgrades.
    (Konstantin Shvachko via cutting)
31. HADOOP-1163. Fix ganglia metrics to aggregate metrics from different hosts properly.
    (Michael Bieniosek via tomwhite)
32. HADOOP-1194. Make compression style record level for map output compression.
    (Arun C Murthy via tomwhite)
33. HADOOP-1187. Improve DFS Scalability: avoid scanning entire list of datanodes in getAdditionalBlocks.
    (Dhruba Borthakur via tomwhite)
34. HADOOP-1133. Add tool to analyze and debug namenode on a production cluster.
    (Dhruba Borthakur via tomwhite)
35. HADOOP-1151. Remove spurious printing to stderr in streaming PipeMapRed.
    (Koji Noguchi via tomwhite)
36. HADOOP-988. Change namenode to use a single map of blocks to metadata.
    (Raghu Angadi via tomwhite)
37. HADOOP-1203. Change UpgradeUtilities used by DFS tests to use MiniDFSCluster to start and stop NameNode/DataNodes.
    (Nigel Daley via tomwhite)
38. HADOOP-1217. Add test.timeout property to build.xml, so that long-running unit tests may be automatically terminated.
    (Nigel Daley via cutting)
39. HADOOP-1149. Improve DFS Scalability: make processOverReplicatedBlock() a no-op if blocks are not over-replicated.
    (Raghu Angadi via tomwhite)
40. HADOOP-1149. Improve DFS Scalability: optimize getDistance(), contains(), and isOnSameRack() in NetworkTopology.
    (Hairong Kuang via tomwhite)
41. HADOOP-1218. Make synchronization on TaskTracker's RunningJob object consistent.
    (Devaraj Das via tomwhite)
42. HADOOP-1219. Ignore progress report once a task has reported as 'done'.
    (Devaraj Das via tomwhite)
43. HADOOP-1114. Permit user to specify additional CLASSPATH elements with a HADOOP_CLASSPATH environment variable.
    (cutting)
44. HADOOP-1198. Remove ipc.client.timeout parameter override from unit test configuration. Using the default is more robust and has almost the same run time.
    (Arun C Murthy via tomwhite)
45. HADOOP-1211. Remove deprecated constructor and unused static members in DataNode class.
    (Konstantin Shvachko via tomwhite)
46. HADOOP-1136. Fix ArrayIndexOutOfBoundsException in FSNamesystem$UnderReplicatedBlocks add() method.
    (Hairong Kuang via tomwhite)
47. HADOOP-978. Add the client name and the address of the node that previously started to create the file to the description of AlreadyBeingCreatedException.
    (Konstantin Shvachko via tomwhite)
48. HADOOP-1001. Check the type of keys and values generated by the mapper against the types specified in JobConf.
    (Tahir Hashmi via tomwhite)
49. HADOOP-971. Improve DFS Scalability: Improve name node performance by adding a hostname to datanodes map.
    (Hairong Kuang via tomwhite)
50. HADOOP-1189. Fix 'No space left on device' exceptions on datanodes.
    (Raghu Angadi via tomwhite)
51. HADOOP-819. Change LineRecordWriter to not insert a tab between key and value when either is null, and to print nothing when both are null.
    (Runping Qi via cutting)
52. HADOOP-1204. Rename InputFormatBase to be FileInputFormat, and deprecate InputFormatBase. Also make LineRecordReader easier to extend.
    (Runping Qi via cutting)
53. HADOOP-1213. Improve logging of errors by IPC server, to consistently include the service name and the call.
    (cutting)
54. HADOOP-1238. Fix metrics reporting by TaskTracker to correctly track maps_running and reduces_running.
    (Michael Bieniosek via cutting)
55. HADOOP-1093. Fix a race condition in HDFS where blocks were sometimes erased before they were reported written.
    (Dhruba Borthakur via cutting)
56. HADOOP-1239. Add a package name to some testjar test classes.
    (Jim Kellerman via cutting)
57. HADOOP-1241. Fix NullPointerException in processReport when namenode is restarted.
    (Dhruba Borthakur via tomwhite)
58. HADOOP-1244. Fix stop-dfs.sh to no longer incorrectly specify slaves file for stopping datanode.
    (Michael Bieniosek via tomwhite)
59. HADOOP-1253. Fix ConcurrentModificationException and NullPointerException in JobControl.
    (Johan Oskarson via tomwhite)
60. HADOOP-1256. Fix NameNode so that multiple DataNodeDescriptors can no longer be created on startup.
    (Hairong Kuang via cutting)
61. HADOOP-1214. Replace streaming classes with new counterparts from Hadoop core.
    (Runping Qi via tomwhite)
62. HADOOP-1250. Move a chmod utility from streaming to FileUtil.
    (omalley via cutting)
63. HADOOP-1258. Fix TestCheckpoint test case to wait for MiniDFSCluster to be active.
    (Nigel Daley via tomwhite)
64. HADOOP-1148. Re-indent all Java source code to consistently use two spaces per indent level.
    (cutting)
65. HADOOP-1251. Add a method to Reporter to get the map InputSplit.
    (omalley via cutting)
66. HADOOP-1224. Fix "Browse the filesystem" link to no longer point to dead datanodes.
    (Enis Soztutar via tomwhite)
67. HADOOP-1154. Fail a streaming task if the threads reading from or writing to the streaming process fail.
    (Koji Noguchi via tomwhite)
68. HADOOP-968. Move shuffle and sort to run in reduce's child JVM, rather than in TaskTracker.
    (Devaraj Das via cutting)
69. HADOOP-1111. Add support for client notification of job completion. If the job configuration has a job.end.notification.url property it will make a HTTP GET request to the specified URL. The number of retries and the interval between retries is also configurable.
    (Alejandro Abdelnur via tomwhite)
70. HADOOP-1275. Fix misspelled job notification property in hadoop-default.xml.
    (Alejandro Abdelnur via tomwhite)
71. HADOOP-1152. Fix race condition in MapOutputCopier.copyOutput file rename causing possible reduce task hang.
    (Tahir Hashmi via tomwhite)
72. HADOOP-1050. Distinguish between failed and killed tasks so as to not count a lost tasktracker against the job.
    (Arun C Murthy via tomwhite)
73. HADOOP-1271. Fix StreamBaseRecordReader to be able to log record data that's not UTF-8.
    (Arun C Murthy via tomwhite)
74. HADOOP-1190. Fix unchecked warnings in main Hadoop code.
    (tomwhite)
75. HADOOP-1127. Fix AlreadyBeingCreatedException in namenode for jobs run with speculative execution.
    (Arun C Murthy via tomwhite)
76. HADOOP-1282. Omnibus HBase patch. Improved tests & configuration.
    (Jim Kellerman via cutting)
77. HADOOP-1262. Make dfs client try to read from a different replica of the checksum file when a checksum error is detected.
    (Hairong Kuang via tomwhite)
78. HADOOP-1279. Fix JobTracker to maintain list of recently completed jobs by order of completion, not submission.
    (Arun C Murthy via cutting)
79. HADOOP-1284. In contrib/streaming, permit flexible specification of field delimiter and fields for partitioning and sorting.
    (Runping Qi via cutting)
80. HADOOP-1176. Fix a bug where reduce would hang when a map had more than 2GB of output for it.
    (Arun C Murthy via cutting)
81. HADOOP-1293. Fix contrib/streaming to print more than the first twenty lines of standard error.
    (Koji Noguchi via cutting)
82. HADOOP-1297. Fix datanode so that requests to remove blocks that do not exist no longer causes block reports to be re-sent every second.
    (Dhruba Borthakur via cutting)
83. HADOOP-1216. Change MapReduce so that, when numReduceTasks is zero, map outputs are written directly as final output, skipping shuffle, sort and reduce. Use this to implement reduce=NONE option in contrib/streaming.
    (Runping Qi via cutting)
84. HADOOP-1294. Fix unchecked warnings in main Hadoop code under Java 6.
    (tomwhite)
85. HADOOP-1299. Fix so that RPC will restart after RPC.stopClient() has been called.
    (Michael Stack via cutting)
86. HADOOP-1278. Improve blacklisting of TaskTrackers by JobTracker, to reduce false positives.
    (Arun C Murthy via cutting)
87. HADOOP-1290. Move contrib/abacus into mapred/lib/aggregate.
    (Runping Qi via cutting)
88. HADOOP-1272. Extract inner classes from FSNamesystem into separate classes.
    (Dhruba Borthakur via tomwhite)
89. HADOOP-1247. Add support to contrib/streaming for aggregate package, formerly called Abacus.
    (Runping Qi via cutting)
90. HADOOP-1061. Fix bug in listing files in the S3 filesystem. NOTE: this change is not backwards compatible! You should use the MigrationTool supplied to migrate existing S3 filesystem data to the new format. Please backup your data first before upgrading (using 'hadoop distcp' for example).
    (tomwhite)
91. HADOOP-1304. Make configurable the maximum number of task attempts before a job fails.
    (Devaraj Das via cutting)
92. HADOOP-1308. Use generics to restrict types when classes are passed as parameters to JobConf methods.
    (Michael Bieniosek via cutting)
93. HADOOP-1312. Fix a ConcurrentModificationException in NameNode that killed the heartbeat monitoring thread.
    (Dhruba Borthakur via cutting)
94. HADOOP-1315. Clean up contrib/streaming, switching it to use core classes more and removing unused code.
    (Runping Qi via cutting)
95. HADOOP-485. Allow a different comparator for grouping keys in calls to reduce.
    (Tahir Hashmi via cutting)
96. HADOOP-1322. Fix TaskTracker blacklisting to work correctly in one- and two-node clusters.
    (Arun C Murthy via cutting)
97. HADOOP-1144. Permit one to specify a maximum percentage of tasks that can fail before a job is aborted. The default is zero.
    (Arun C Murthy via cutting)
98. HADOOP-1184. Fix HDFS decomissioning to complete when the only copy of a block is on a decommissioned node.
    (Dhruba Borthakur via cutting)
99. HADOOP-1263. Change DFSClient to retry certain namenode calls with a random, exponentially increasing backoff time, to avoid overloading the namenode on, e.g., job start.
    (Hairong Kuang via cutting)
100. HADOOP-1325. First complete, functioning version of HBase.
     (Jim Kellerman via cutting)
101. HADOOP-1276. Make tasktracker expiry interval configurable.
     (Arun C Murthy via cutting)
102. HADOOP-1326. Change JobClient#RunJob() to return the job.
     (omalley via cutting)
103. HADOOP-1270. Randomize the fetch of map outputs, speeding the shuffle.
     (Arun C Murthy via cutting)
104. HADOOP-1200. Restore disk checking lost in HADOOP-1170.
     (Hairong Kuang via cutting)
105. HADOOP-1252. Changed MapReduce's allocation of local files to use round-robin among available devices, rather than a hashcode. More care is also taken to not allocate files on full or offline drives.
     (Devaraj Das via cutting)
106. HADOOP-1324. Change so that an FSError kills only the task that generates it rather than the entire task tracker.
     (Arun C Murthy via cutting)
107. HADOOP-1310. Fix unchecked warnings in aggregate code.
     (tomwhite)
108. HADOOP-1255. Fix a bug where the namenode falls into an infinite loop trying to remove a dead node.
     (Hairong Kuang via cutting)
109. HADOOP-1160. Fix DistributedFileSystem.close() to close the underlying FileSystem, correctly aborting files being written.
     (Hairong Kuang via cutting)
110. HADOOP-1341. Fix intermittent failures in HBase unit tests caused by deadlock.
     (Jim Kellerman via cutting)
111. HADOOP-1350. Fix shuffle performance problem caused by forcing chunked encoding of map outputs.
     (Devaraj Das via cutting)
112. HADOOP-1345. Fix HDFS to correctly retry another replica when a checksum error is encountered.
     (Hairong Kuang via cutting)
113. HADOOP-1205. Improve synchronization around HDFS block map.
     (Hairong Kuang via cutting)
114. HADOOP-1353. Fix a potential NullPointerException in namenode.
     (Dhruba Borthakur via cutting)
115. HADOOP-1354. Fix a potential NullPointerException in FsShell.
     (Hairong Kuang via cutting)
116. HADOOP-1358. Fix a potential bug when DFSClient calls skipBytes.
     (Hairong Kuang via cutting)
117. HADOOP-1356. Fix a bug in ValueHistogram.
     (Runping Qi via cutting)
118. HADOOP-1363. Fix locking bug in JobClient#waitForCompletion().
     (omalley via cutting)
119. HADOOP-1368. Fix inconsistent synchronization in JobInProgress.
     (omalley via cutting)
120. HADOOP-1369. Fix inconsistent synchronization in TaskTracker.
     (omalley via cutting)
121. HADOOP-1361. Fix various calls to skipBytes() to check return value.
     (Hairong Kuang via cutting)
122. HADOOP-1388. Fix a potential NullPointerException in web ui.
     (Devaraj Das via cutting)
123. HADOOP-1385. Fix MD5Hash#hashCode() to generally hash to more than 256 values.
     (omalley via cutting)
124. HADOOP-1386. Fix Path to not permit the empty string as a path, as this has lead to accidental file deletion. Instead force applications to use "." to name the default directory.
     (Hairong Kuang via cutting)
125. HADOOP-1407. Fix integer division bug in JobInProgress which meant failed tasks didn't cause the job to fail.
     (Arun C Murthy via tomwhite)
126. HADOOP-1427. Fix a typo that caused GzipCodec to incorrectly use a very small input buffer.
     (Espen Amble Kolstad via cutting)
127. HADOOP-1435. Fix globbing code to no longer use the empty string to indicate the default directory, per HADOOP-1386.
     (Hairong Kuang via cutting)
128. HADOOP-1411. Make task retry framework handle AlreadyBeingCreatedException when wrapped as a RemoteException.
     (Hairong Kuang via tomwhite)
129. HADOOP-1242. Improve handling of DFS upgrades.
     (Konstantin Shvachko via cutting)
130. HADOOP-1332. Fix so that TaskTracker exits reliably during unit tests on Windows.
     (omalley via cutting)
131. HADOOP-1431. Fix so that sort progress reporting during map runs only while sorting, so that stuck maps are correctly terminated.
     (Devaraj Das and Arun C Murthy via cutting)
132. HADOOP-1452. Change TaskTracker.MapOutputServlet.doGet.totalRead to a long, permitting map outputs to exceed 2^31 bytes.
     (omalley via cutting)
133. HADOOP-1443. Fix a bug opening zero-length files in HDFS.
     (Konstantin Shvachko via cutting)

### Release 0.12.3 - 2007-04-06

1. HADOOP-1162. Fix bug in record CSV and XML serialization of binary values.
   (Milind Bhandarkar via cutting)
2. HADOOP-1123. Fix NullPointerException in LocalFileSystem when trying to recover from a checksum error.
   (Hairong Kuang & Nigel Daley via tomwhite)
3. HADOOP-1177. Fix bug where IOException in MapOutputLocation.getFile was not being logged.
   (Devaraj Das via tomwhite)
4. HADOOP-1175. Fix bugs in JSP for displaying a task's log messages.
   (Arun C Murthy via cutting)
5. HADOOP-1191. Fix map tasks to wait until sort progress thread has stopped before reporting the task done.
   (Devaraj Das via cutting)
6. HADOOP-1192. Fix an integer overflow bug in FSShell's 'dus' command and a performance problem in HDFS's implementation of it.
   (Hairong Kuang via cutting)
7. HADOOP-1105. Fix reducers to make "progress" while iterating through values.
   (Devaraj Das & Owen O'Malley via tomwhite)
8. HADOOP-1179. Make Task Tracker close index file as soon as the read is done when serving get-map-output requests.
   (Devaraj Das via tomwhite)

### Release 0.12.2 - 2007-23-17

1. HADOOP-1135. Fix bug in block report processing which may cause the namenode to delete blocks.
   (Dhruba Borthakur via tomwhite)
2. HADOOP-1145. Make XML serializer and deserializer classes public in record package.
   (Milind Bhandarkar via cutting)
3. HADOOP-1140. Fix a deadlock in metrics.
   (David Bowen via cutting)
4. HADOOP-1150. Fix streaming -reducer and -mapper to give them defaults.
   (Owen O'Malley via tomwhite)

### Release 0.12.1 - 2007-03-17

1. HADOOP-1035. Fix a StackOverflowError in FSDataSet.
   (Raghu Angadi via cutting)
2. HADOOP-1053. Fix VInt representation of negative values. Also remove references in generated record code to methods outside of the record package and improve some record documentation.
   (Milind Bhandarkar via cutting)
3. HADOOP-1067. Compile fails if Checkstyle jar is present in lib directory. Also remove dependency on a particular Checkstyle version number.
   (tomwhite)
4. HADOOP-1060. Fix an IndexOutOfBoundsException in the JobTracker that could cause jobs to hang.
   (Arun C Murthy via cutting)
5. HADOOP-1077. Fix a race condition fetching map outputs that could hang reduces.
   (Devaraj Das via cutting)
6. HADOOP-1083. Fix so that when a cluster restarts with a missing datanode, its blocks are replicated.
   (Hairong Kuang via cutting)
7. HADOOP-1082. Fix a NullPointerException in ChecksumFileSystem.
   (Hairong Kuang via cutting)
8. HADOOP-1088. Fix record serialization of negative values.
   (Milind Bhandarkar via cutting)
9. HADOOP-1080. Fix bug in bin/hadoop on Windows when native libraries are present.
   (ab via cutting)
10. HADOOP-1091. Fix a NullPointerException in MetricsRecord.
    (David Bowen via tomwhite)
11. HADOOP-1092. Fix a NullPointerException in HeartbeatMonitor thread.
    (Hairong Kuang via tomwhite)
12. HADOOP-1112. Fix a race condition in Hadoop metrics.
    (David Bowen via tomwhite)
13. HADOOP-1108. Checksummed file system should retry reading if a different replica is found when handling ChecksumException.
    (Hairong Kuang via tomwhite)
14. HADOOP-1070. Fix a problem with number of racks and datanodes temporarily doubling.
    (Konstantin Shvachko via tomwhite)
15. HADOOP-1099. Fix NullPointerException in JobInProgress.
    (Gautam Kowshik via tomwhite)
16. HADOOP-1115. Fix bug where FsShell copyToLocal doesn't copy directories.
    (Hairong Kuang via tomwhite)
17. HADOOP-1109. Fix NullPointerException in StreamInputFormat.
    (Koji Noguchi via tomwhite)
18. HADOOP-1117. Fix DFS scalability: when the namenode is restarted it consumes 80% CPU.
    (Dhruba Borthakur via tomwhite)
19. HADOOP-1089. Make the C++ version of write and read v-int agree with the Java versions.
    (Milind Bhandarkar via tomwhite)
20. HADOOP-1096. Rename InputArchive and OutputArchive and make them public.
    (Milind Bhandarkar via tomwhite)
21. HADOOP-1128. Fix missing progress information in map tasks.
    (Espen Amble Kolstad, Andrzej Bialecki, and Owen O'Malley via tomwhite)
22. HADOOP-1129. Fix DFSClient to not hide IOExceptions in flush method.
    (Hairong Kuang via tomwhite)
23. HADOOP-1126. Optimize CPU usage for under replicated blocks when cluster restarts.
    (Hairong Kuang via tomwhite)

### Release 0.12.0 - 2007-03-02

1. HADOOP-975. Separate stdout and stderr from tasks.
   (Arun C Murthy via cutting)
2. HADOOP-982. Add some setters and a toString() method to BytesWritable.
   (omalley via cutting)
3. HADOOP-858. Move contrib/smallJobsBenchmark to src/test, removing obsolete bits.
   (Nigel Daley via cutting)
4. HADOOP-992. Fix MiniMR unit tests to use MiniDFS when specified, rather than the local FS.
   (omalley via cutting)
5. HADOOP-954. Change use of metrics to use callback mechanism. Also rename utility class Metrics to MetricsUtil.
   (David Bowen & Nigel Daley via cutting)
6. HADOOP-893. Improve HDFS client's handling of dead datanodes. The set is no longer reset with each block, but rather is now maintained for the life of an open file.
   (Raghu Angadi via cutting)
7. HADOOP-882. Upgrade to jets3t version 0.5, used by the S3 FileSystem. This version supports retries.
   (Michael Stack via cutting)
8. HADOOP-977. Send task's stdout and stderr to JobClient's stdout and stderr respectively, with each line tagged by the task's name.
   (Arun C Murthy via cutting)
9. HADOOP-761. Change unit tests to not use /tmp.
   (Nigel Daley via cutting)
10. HADOOP-1007. Make names of metrics used in Hadoop unique.
    (Nigel Daley via cutting)
11. HADOOP-491. Change mapred.task.timeout to be per-job, and make a value of zero mean no timeout. Also change contrib/streaming to disable task timeouts.
    (Arun C Murthy via cutting)
12. HADOOP-1010. Add Reporter.NULL, a Reporter implementation that does nothing.
    (Runping Qi via cutting)
13. HADOOP-923. In HDFS NameNode, move replication computation to a separate thread, to improve heartbeat processing time.
    (Dhruba Borthakur via cutting)
14. HADOOP-476. Rewrite contrib/streaming command-line processing, improving parameter validation.
    (Sanjay Dahiya via cutting)
15. HADOOP-973. Improve error messages in Namenode. This should help to track down a problem that was appearing as a NullPointerException.
    (Dhruba Borthakur via cutting)
16. HADOOP-649. Fix so that jobs with no tasks are not lost.
    (Thomas Friol via cutting)
17. HADOOP-803. Reduce memory use by HDFS namenode, phase I.
    (Raghu Angadi via cutting)
18. HADOOP-1021. Fix MRCaching-based unit tests on Windows.
    (Nigel Daley via cutting)
19. HADOOP-889. Remove duplicate code from HDFS unit tests.
    (Milind Bhandarkar via cutting)
20. HADOOP-943. Improve HDFS's fsck command to display the filename for under-replicated blocks.
    (Dhruba Borthakur via cutting)
21. HADOOP-333. Add validator for sort benchmark output.
    (Arun C Murthy via cutting)
22. HADOOP-947. Improve performance of datanode decomissioning.
    (Dhruba Borthakur via cutting)
23. HADOOP-442. Permit one to specify hosts allowed to connect to namenode and jobtracker with include and exclude files.
    (Wendy Chien via cutting)
24. HADOOP-1017. Cache constructors, for improved performance.
    (Ron Bodkin via cutting)
25. HADOOP-867. Move split creation out of JobTracker to client. Splits are now saved in a separate file, read by task processes directly, so that user code is no longer required in the JobTracker.
    (omalley via cutting)
26. HADOOP-1006. Remove obsolete '-local' option from test code.
    (Gautam Kowshik via cutting)
27. HADOOP-952. Create a public (shared) Hadoop EC2 AMI. The EC2 scripts now support launch of public AMIs.
    (tomwhite)
28. HADOOP-1025. Remove some obsolete code in ipc.Server.
    (cutting)
29. HADOOP-997. Implement S3 retry mechanism for failed block transfers. This includes a generic retry mechanism for use elsewhere in Hadoop.
    (tomwhite)
30. HADOOP-990. Improve HDFS support for full datanode volumes.
    (Raghu Angadi via cutting)
31. HADOOP-564. Replace uses of "dfs://" URIs with the more standard "hdfs://".
    (Wendy Chien via cutting)
32. HADOOP-1030. In unit tests, unify setting of ipc.client.timeout. Also increase the value used from one to two seconds, in hopes of making tests complete more reliably.
    (cutting)
33. HADOOP-654. Stop assigning tasks to a tasktracker if it has failed more than a specified number in the job.
    (Arun C Murthy via cutting)
34. HADOOP-985. Change HDFS to identify nodes by IP address rather than by DNS hostname.
    (Raghu Angadi via cutting)
35. HADOOP-248. Optimize location of map outputs to not use random probes.
    (Devaraj Das via cutting)
36. HADOOP-1029. Fix streaming's input format to correctly seek to the start of splits.
    (Arun C Murthy via cutting)
37. HADOOP-492. Add per-job and per-task counters. These are incremented via the Reporter interface and available through the web ui and the JobClient API. The mapreduce framework maintains a few basic counters, and applications may add their own. Counters are also passed to the metrics system.
    (David Bowen via cutting)
38. HADOOP-1034. Fix datanode to better log exceptions.
    (Philippe Gassmann via cutting)
39. HADOOP-878. In contrib/streaming, fix reducer=NONE to work with multiple maps.
    (Arun C Murthy via cutting)
40. HADOOP-1039. In HDFS's TestCheckpoint, avoid restarting MiniDFSCluster so often, speeding this test.
    (Dhruba Borthakur via cutting)
41. HADOOP-1040. Update RandomWriter example to use counters and user-defined input and output formats.
    (omalley via cutting)
42. HADOOP-1027. Fix problems with in-memory merging during shuffle and re-enable this optimization.
    (Devaraj Das via cutting)
43. HADOOP-1036. Fix exception handling in TaskTracker to keep tasks from being lost.
    (Arun C Murthy via cutting)
44. HADOOP-1042. Improve the handling of failed map output fetches.
    (Devaraj Das via cutting)
45. HADOOP-928. Make checksums optional per FileSystem.
    (Hairong Kuang via cutting)
46. HADOOP-1044. Fix HDFS's TestDecommission to not spuriously fail.
    (Wendy Chien via cutting)
47. HADOOP-972. Optimize HDFS's rack-aware block placement algorithm.
    (Hairong Kuang via cutting)
48. HADOOP-1043. Optimize shuffle, increasing parallelism.
    (Devaraj Das via cutting)
49. HADOOP-940. Improve HDFS's replication scheduling.
    (Dhruba Borthakur via cutting)
50. HADOOP-1020. Fix a bug in Path resolution, and a with unit tests on Windows.
    (cutting)
51. HADOOP-941. Enhance record facility.
    (Milind Bhandarkar via cutting)
52. HADOOP-1000. Fix so that log messages in task subprocesses are not written to a task's standard error.
    (Arun C Murthy via cutting)
53. HADOOP-1037. Fix bin/slaves.sh, which currently only works with /bin/bash, to specify /bin/bash rather than /bin/sh.
    (cutting)
54. HADOOP-1046. Clean up tmp from partially received stale block files.
    (ab)
55. HADOOP-1041. Optimize mapred counter implementation. Also group counters by their declaring Enum.
    (David Bowen via cutting)
56. HADOOP-1032. Permit one to specify jars that will be cached across multiple jobs.
    (Gautam Kowshik via cutting)
57. HADOOP-1051. Add optional checkstyle task to build.xml. To use this developers must download the (LGPL'd) checkstyle jar themselves.
    (tomwhite via cutting)
58. HADOOP-1049. Fix a race condition in IPC client.
    (Devaraj Das via cutting)
59. HADOOP-1056. Check HDFS include/exclude node lists with both IP address and hostname.
    (Wendy Chien via cutting)
60. HADOOP-994. In HDFS, limit the number of blocks invalidated at once. Large lists were causing datenodes to timeout.
    (Dhruba Borthakur via cutting)
61. HADOOP-432. Add a trash feature, disabled by default. When enabled, the FSShell 'rm' command will move things to a trash directory in the filesystem. In HDFS, a thread periodically checkpoints the trash and removes old checkpoints.
    (cutting)

### Release 0.11.2 - 2007-02-16

1. HADOOP-1009. Fix an infinite loop in the HDFS namenode.
   (Dhruba Borthakur via cutting)
2. HADOOP-1014. Disable in-memory merging during shuffle, as this is causing data corruption.
   (Devaraj Das via cutting)

### Release 0.11.1 - 2007-02-09

1. HADOOP-976. Make SequenceFile.Metadata public.
   (Runping Qi via cutting)
2. HADOOP-917. Fix a NullPointerException in SequenceFile's merger with large map outputs.
   (omalley via cutting)
3. HADOOP-984. Fix a bug in shuffle error handling introduced by HADOOP-331. If a map output is unavailable, the job tracker is once more informed.
   (Arun C Murthy via cutting)
4. HADOOP-987. Fix a problem in HDFS where blocks were not removed from neededReplications after a replication target was selected.
   (Hairong Kuang via cutting)

### Release 0.11.0 - 2007-02-02

1. HADOOP-781. Remove methods deprecated in 0.10 that are no longer widely used.
   (cutting)
2. HADOOP-842. Change HDFS protocol so that the open() method is passed the client hostname, to permit the namenode to order block locations on the basis of network topology.
   (Hairong Kuang via cutting)
3. HADOOP-852. Add an ant task to compile record definitions, and use it to compile record unit tests.
   (Milind Bhandarkar via cutting)
4. HADOOP-757. Fix "Bad File Descriptor" exception in HDFS client when an output file is closed twice.
   (Raghu Angadi via cutting)
5. [ intentionally blank ]
6. HADOOP-890. Replace dashes in metric names with underscores, for better compatibility with some monitoring systems.
   (Nigel Daley via cutting)
7. HADOOP-801. Add to jobtracker a log of task completion events.
   (Sanjay Dahiya via cutting)
8. HADOOP-855. In HDFS, try to repair files with checksum errors. An exception is still thrown, but corrupt blocks are now removed when they have replicas.
   (Wendy Chien via cutting)
9. HADOOP-886. Reduce number of timer threads created by metrics API by pooling contexts.
   (Nigel Daley via cutting)
10. HADOOP-897. Add a "javac.args" property to build.xml that permits one to pass arbitrary options to javac.
    (Milind Bhandarkar via cutting)
11. HADOOP-899. Update libhdfs for changes in HADOOP-871.
    (Sameer Paranjpye via cutting)
12. HADOOP-905. Remove some dead code from JobClient.
    (cutting)
13. HADOOP-902. Fix a NullPointerException in HDFS client when closing output streams.
    (Raghu Angadi via cutting)
14. HADOOP-735. Switch generated record code to use BytesWritable to represent fields of type 'buffer'.
    (Milind Bhandarkar via cutting)
15. HADOOP-830. Improve mapreduce merge performance by buffering and merging multiple map outputs as they arrive at reduce nodes before they're written to disk.
    (Devaraj Das via cutting)
16. HADOOP-908. Add a new contrib package, Abacus, that simplifies counting and aggregation, built on MapReduce.
    (Runping Qi via cutting)
17. HADOOP-901. Add support for recursive renaming to the S3 filesystem.
    (Tom White via cutting)
18. HADOOP-912. Fix a bug in TaskTracker.isIdle() that was sporadically causing unit test failures.
    (Arun C Murthy via cutting)
19. HADOOP-909. Fix the 'du' command to correctly compute the size of FileSystem directory trees.
    (Hairong Kuang via cutting)
20. HADOOP-731. When a checksum error is encountered on a file stored in HDFS, try another replica of the data, if any.
    (Wendy Chien via cutting)
21. HADOOP-732. Add support to SequenceFile for arbitrary metadata, as a set of attribute value pairs.
    (Runping Qi via cutting)
22. HADOOP-929. Fix PhasedFileSystem to pass configuration to underlying FileSystem.
    (Sanjay Dahiya via cutting)
23. HADOOP-935. Fix contrib/abacus to not delete pre-existing output files, but rather to fail in this case.
    (Runping Qi via cutting)
24. HADOOP-936. More metric renamings, as in HADOOP-890.
    (Nigel Daley via cutting)
25. HADOOP-856. Fix HDFS's fsck command to not report that non-existent filesystems are healthy.
    (Milind Bhandarkar via cutting)
26. HADOOP-602. Remove the dependency on Lucene's PriorityQueue utility, by copying it into Hadoop. This facilitates using Hadoop with different versions of Lucene without worrying about CLASSPATH order.
    (Milind Bhandarkar via cutting)
27. [ intentionally blank ]
28. HADOOP-227. Add support for backup namenodes, which periodically get snapshots of the namenode state.
    (Dhruba Borthakur via cutting)
29. HADOOP-884. Add scripts in contrib/ec2 to facilitate running Hadoop on an Amazon's EC2 cluster.
    (Tom White via cutting)
30. HADOOP-937. Change the namenode to request re-registration of datanodes in more circumstances.
    (Hairong Kuang via cutting)
31. HADOOP-922. Optimize small forward seeks in HDFS. If data is has likely already in flight, skip ahead rather than re-opening the block.
    (Dhruba Borthakur via cutting)
32. HADOOP-961. Add a 'job -events' sub-command that prints job events, including task completions and failures.
    (omalley via cutting)
33. HADOOP-959. Fix namenode snapshot code added in HADOOP-227 to work on Windows.
    (Dhruba Borthakur via cutting)
34. HADOOP-934. Fix TaskTracker to catch metrics exceptions that were causing heartbeats to fail.
    (Arun Murthy via cutting)
35. HADOOP-881. Fix JobTracker web interface to display the correct number of task failures.
    (Sanjay Dahiya via cutting)
36. HADOOP-788. Change contrib/streaming to subclass TextInputFormat, permitting it to take advantage of native compression facilities.
    (Sanjay Dahiya via cutting)
37. HADOOP-962. In contrib/ec2: make scripts executable in tar file; add a README; make the environment file use a template.
    (Tom White via cutting)
38. HADOOP-549. Fix a NullPointerException in TaskReport's serialization.
    (omalley via cutting)
39. HADOOP-963. Fix remote exceptions to have the stack trace of the caller thread, not the IPC listener thread.
    (omalley via cutting)
40. HADOOP-967. Change RPC clients to start sending a version header.
    (omalley via cutting)
41. HADOOP-964. Fix a bug introduced by HADOOP-830 where jobs failed whose comparators and/or i/o types were in the job's jar.
    (Dennis Kubes via cutting)
42. HADOOP-969. Fix a deadlock in JobTracker.
    (omalley via cutting)
43. HADOOP-862. Add support for the S3 FileSystem to the CopyFiles tool.
    (Michael Stack via cutting)
44. HADOOP-965. Fix IsolationRunner so that job's jar can be found.
    (Dennis Kubes via cutting)
45. HADOOP-309. Fix two NullPointerExceptions in StatusHttpServer.
    (navychen via cutting)
46. HADOOP-692. Add rack awareness to HDFS's placement of blocks.
    (Hairong Kuang via cutting)

### Release 0.10.1 - 2007-01-10

1. HADOOP-857. Fix S3 FileSystem implementation to permit its use for MapReduce input and output.
   (Tom White via cutting)
2. HADOOP-863. Reduce logging verbosity introduced by HADOOP-813.
   (Devaraj Das via cutting)
3. HADOOP-815. Fix memory leaks in JobTracker.
   (Arun C Murthy via cutting)
4. HADOOP-600. Fix a race condition in JobTracker.
   (Arun C Murthy via cutting)
5. HADOOP-864. Fix 'bin/hadoop -jar' to operate correctly when hadoop.tmp.dir does not yet exist.
   (omalley via cutting)
6. HADOOP-866. Fix 'dfs -get' command to remove existing crc files, if any.
   (Milind Bhandarkar via cutting)
7. HADOOP-871. Fix a bug in bin/hadoop setting JAVA_LIBRARY_PATH.
   (Arun C Murthy via cutting)
8. HADOOP-868. Decrease the number of open files during map, respecting io.sort.fa ctor.
   (Devaraj Das via cutting)
9. HADOOP-865. Fix S3 FileSystem so that partially created files can be deleted.
   (Tom White via cutting)
10. HADOOP-873. Pass java.library.path correctly to child processes.
    (omalley via cutting)
11. HADOOP-851. Add support for the LZO codec. This is much faster than the default, zlib-based compression, but it is only available when the native library is built.
    (Arun C Murthy via cutting)
12. HADOOP-880. Fix S3 FileSystem to remove directories.
    (Tom White via cutting)
13. HADOOP-879. Fix InputFormatBase to handle output generated by MapFileOutputFormat.
    (cutting)
14. HADOOP-659. In HDFS, prioritize replication of blocks based on current replication level. Blocks which are severely under-replicated should be further replicated before blocks which are less under-replicated.
    (Hairong Kuang via cutting)
15. HADOOP-726. Deprecate FileSystem locking methods. They are not currently usable. Locking should eventually provided as an independent service.
    (Raghu Angadi via cutting)
16. HADOOP-758. Fix exception handling during reduce so that root exceptions are not masked by exceptions in cleanups.
    (Raghu Angadi via cutting)

### Release 0.10.0 - 2007-01-05

1. HADOOP-763. Change DFS namenode benchmark to not use MapReduce.
   (Nigel Daley via cutting)
2. HADOOP-777. Use fully-qualified hostnames for tasktrackers and datanodes.
   (Mahadev Konar via cutting)
3. HADOOP-621. Change 'dfs -cat' to exit sooner when output has been closed.
   (Dhruba Borthakur via cutting)
4. HADOOP-752. Rationalize some synchronization in DFS namenode.
   (Dhruba Borthakur via cutting)
5. HADOOP-629. Fix RPC services to better check the protocol name and version.
   (omalley via cutting)
6. HADOOP-774. Limit the number of invalid blocks returned with heartbeats by the namenode to datanodes. Transmitting and processing very large invalid block lists can tie up both the namenode and datanode for too long.
   (Dhruba Borthakur via cutting)
7. HADOOP-738. Change 'dfs -get' command to not create CRC files by default, adding a -crc option to force their creation.
   (Milind Bhandarkar via cutting)
8. HADOOP-676. Improved exceptions and error messages for common job input specification errors.
   (Sanjay Dahiya via cutting)
9. [Included in 0.9.2 release]
10. HADOOP-756. Add new dfsadmin option to wait for filesystem to be operational.
    (Dhruba Borthakur via cutting)
11. HADOOP-770. Fix jobtracker web interface to display, on restart, jobs that were running when it was last stopped.
    (Sanjay Dahiya via cutting)
12. HADOOP-331. Write all map outputs to a single file with an index, rather than to a separate file per reduce task. This should both speed the shuffle and make things more scalable.
    (Devaraj Das via cutting)
13. HADOOP-818. Fix contrib unit tests to not depend on core unit tests.
    (omalley via cutting)
14. HADOOP-786. Log common exception at debug level.
    (Sanjay Dahiya via cutting)
15. HADOOP-796. Provide more convenient access to failed task information in the web interface.
    (Sanjay Dahiya via cutting)
16. HADOOP-764. Reduce memory allocations in namenode some.
    (Dhruba Borthakur via cutting)
17. HADOOP-802. Update description of mapred.speculative.execution to mention reduces.
    (Nigel Daley via cutting)
18. HADOOP-806. Include link to datanodes on front page of namenode web interface.
    (Raghu Angadi via cutting)
19. HADOOP-618. Make JobSubmissionProtocol public.
    (Arun C Murthy via cutting)
20. HADOOP-782. Fully remove killed tasks.
    (Arun C Murthy via cutting)
21. HADOOP-792. Fix 'dfs -mv' to return correct status.
    (Dhruba Borthakur via cutting)
22. HADOOP-673. Give each task its own working directory again.
    (Mahadev Konar via cutting)
23. HADOOP-571. Extend the syntax of Path to be a URI; to be optionally qualified with a scheme and authority. The scheme determines the FileSystem implementation, while the authority determines the FileSystem instance. New FileSystem implementations may be provided by defining an fs.<scheme>.impl property, naming the FileSystem implementation class. This permits easy integration of new FileSystem implementations.
    (cutting)
24. HADOOP-720. Add an HDFS white paper to website.
    (Dhruba Borthakur via cutting)
25. HADOOP-794. Fix a divide-by-zero exception when a job specifies zero map tasks.
    (omalley via cutting)
26. HADOOP-454. Add a 'dfs -dus' command that provides summary disk usage.
    (Hairong Kuang via cutting)
27. HADOOP-574. Add an Amazon S3 implementation of FileSystem. To use this, one need only specify paths of the form s3://id:secret@bucket/. Alternately, the AWS access key id and secret can be specified in your config, with the properties fs.s3.awsAccessKeyId and fs.s3.awsSecretAccessKey.
    (Tom White via cutting)
28. HADOOP-824. Rename DFSShell to be FsShell, since it applies generically to all FileSystem implementations.
    (cutting)
29. HADOOP-813. Fix map output sorting to report progress, so that sorts which take longer than the task timeout do not fail.
    (Devaraj Das via cutting)
30. HADOOP-825. Fix HDFS daemons when configured with new URI syntax.
    (omalley via cutting)
31. HADOOP-596. Fix a bug in phase reporting during reduce.
    (Sanjay Dahiya via cutting)
32. HADOOP-811. Add a utility, MultithreadedMapRunner.
    (Alejandro Abdelnur via cutting)
33. HADOOP-829. Within HDFS, clearly separate three different representations for datanodes: one for RPCs, one for namenode-internal use, and one for namespace persistence.
    (Dhruba Borthakur via cutting)
34. HADOOP-823. Fix problem starting datanode when not all configured data directories exist.
    (Bryan Pendleton via cutting)
35. HADOOP-451. Add a Split interface. CAUTION: This incompatibly changes the InputFormat and RecordReader interfaces. Not only is FileSplit replaced with Split, but a FileSystem parameter is no longer passed in several methods, input validation has changed, etc.
    (omalley via cutting)
36. HADOOP-814. Optimize locking in namenode.
    (Dhruba Borthakur via cutting)
37. HADOOP-738. Change 'fs -put' and 'fs -get' commands to accept standard input and output, respectively. Standard i/o is specified by a file named '-'.
    (Wendy Chien via cutting)
38. HADOOP-835. Fix a NullPointerException reading record-compressed SequenceFiles.
    (Hairong Kuang via cutting)
39. HADOOP-836. Fix a MapReduce bug on Windows, where the wrong FileSystem was used. Also add a static FileSystem.getLocal() method and better Path checking in HDFS, to help avoid such issues in the future.
    (omalley via cutting)
40. HADOOP-837. Improve RunJar utility to unpack jar file hadoop.tmp.dir, rather than the system temporary directory.
    (Hairong Kuang via cutting)
41. HADOOP-841. Fix native library to build 32-bit version even when on a 64-bit host, if a 32-bit JVM is used.
    (Arun C Murthy via cutting)
42. HADOOP-838. Fix tasktracker to pass java.library.path to sub-processes, so that libhadoop.a is found.
    (Arun C Murthy via cutting)
43. HADOOP-844. Send metrics messages on a fixed-delay schedule instead of a fixed-rate schedule.
    (David Bowen via cutting)
44. HADOOP-849. Fix OutOfMemory exceptions in TaskTracker due to a file handle leak in SequenceFile.
    (Devaraj Das via cutting)
45. HADOOP-745. Fix a synchronization bug in the HDFS namenode.
    (Dhruba Borthakur via cutting)
46. HADOOP-850. Add Writable implementations for variable-length integers.
    (ab via cutting)
47. HADOOP-525. Add raw comparators to record types. This greatly improves record sort performance.
    (Milind Bhandarkar via cutting)
48. HADOOP-628. Fix a problem with 'fs -cat' command, where some characters were replaced with question marks.
    (Wendy Chien via cutting)
49. HADOOP-804. Reduce verbosity of MapReduce logging.
    (Sanjay Dahiya via cutting)
50. HADOOP-853. Rename 'site' to 'docs', in preparation for inclusion in releases.
    (cutting)
51. HADOOP-371. Include contrib jars and site documentation in distributions. Also add contrib and example documentation to distributed javadoc, in separate sections.
    (Nigel Daley via cutting)
52. HADOOP-846. Report progress during entire map, as sorting of intermediate outputs may happen at any time, potentially causing task timeouts.
    (Devaraj Das via cutting)
53. HADOOP-840. In task tracker, queue task cleanups and perform them in a separate thread.
    (omalley & Mahadev Konar via cutting)
54. HADOOP-681. Add to HDFS the ability to decommission nodes. This causes their blocks to be re-replicated on other nodes, so that they may be removed from a cluster.
    (Dhruba Borthakur via cutting)
55. HADOOP-470. In HDFS web ui, list the datanodes containing each copy of a block.
    (Hairong Kuang via cutting)
56. HADOOP-700. Change bin/hadoop to only include core jar file on classpath, not example, test, etc. Also rename core jar to hadoop-${version}-core.jar so that it can be more easily identified.
    (Nigel Daley via cutting)
57. HADOOP-619. Extend InputFormatBase to accept individual files and glob patterns as MapReduce inputs, not just directories. Also change contrib/streaming to use this.
    (Sanjay Dahia via cutting)

### Release 0.9.2 - 2006-12-15

1. HADOOP-639. Restructure InterTrackerProtocol to make task accounting more reliable.
   (Arun C Murthy via cutting)
2. HADOOP-827. Turn off speculative execution by default, since it's currently broken.
   (omalley via cutting)
3. HADOOP-791. Fix a deadlock in the task tracker.
   (Mahadev Konar via cutting)

### Release 0.9.1 - 2006-12-06

1. HADOOP-780. Use ReflectionUtils to instantiate key and value objects.
   (ab)
2. HADOOP-779. Fix contrib/streaming to work correctly with gzipped input files.
   (Hairong Kuang via cutting)

### Release 0.9.0 - 2006-12-01

1. HADOOP-655. Remove most deprecated code. A few deprecated things remain, notably UTF8 and some methods that are still required. Also cleaned up constructors for SequenceFile, MapFile, SetFile, and ArrayFile a bit.
   (cutting)
2. HADOOP-565. Upgrade to Jetty version 6.
   (Sanjay Dahiya via cutting)
3. HADOOP-682. Fix DFS format command to work correctly when configured with a non-existent directory.
   (Sanjay Dahiya via cutting)
4. HADOOP-645. Fix a bug in contrib/streaming when -reducer is NONE.
   (Dhruba Borthakur via cutting)
5. HADOOP-687. Fix a classpath bug in bin/hadoop that blocked the servers from starting.
   (Sameer Paranjpye via omalley)
6. HADOOP-683. Remove a script dependency on bash, so it works with dash, the new default for /bin/sh on Ubuntu.
   (James Todd via cutting)
7. HADOOP-382. Extend unit tests to run multiple datanodes.
   (Milind Bhandarkar via cutting)
8. HADOOP-604. Fix some synchronization issues and a NullPointerException in DFS datanode.
   (Raghu Angadi via cutting)
9. HADOOP-459. Fix memory leaks and a host of other issues with libhdfs.
   (Sameer Paranjpye via cutting)
10. HADOOP-694. Fix a NullPointerException in jobtracker.
    (Mahadev Konar via cutting)
11. HADOOP-637. Fix a memory leak in the IPC server. Direct buffers are not collected like normal buffers, and provided little advantage.
    (Raghu Angadi via cutting)
12. HADOOP-696. Fix TestTextInputFormat unit test to not rely on the order of directory listings.
    (Sameer Paranjpye via cutting)
13. HADOOP-611. Add support for iterator-based merging to SequenceFile.
    (Devaraj Das via cutting)
14. HADOOP-688. Move DFS administrative commands to a separate command named 'dfsadmin'.
    (Dhruba Borthakur via cutting)
15. HADOOP-708. Fix test-libhdfs to return the correct status, so that failures will break the build.
    (Nigel Daley via cutting)
16. HADOOP-646. Fix namenode to handle edits files larger than 2GB.
    (Milind Bhandarkar via cutting)
17. HADOOP-705. Fix a bug in the JobTracker when failed jobs were not completely cleaned up.
    (Mahadev Konar via cutting)
18. HADOOP-613. Perform final merge while reducing. This removes one sort pass over the data and should consequently significantly decrease overall processing time.
    (Devaraj Das via cutting)
19. HADOOP-661. Make each job's configuration visible through the web ui.
    (Arun C Murthy via cutting)
20. HADOOP-489. In MapReduce, separate user logs from system logs. Each task's log output is now available through the web ui.
    (Arun C Murthy via cutting)
21. HADOOP-712. Fix record io's xml serialization to correctly handle control-characters.
    (Milind Bhandarkar via cutting)
22. HADOOP-668. Improvements to the web-based DFS browser.
    (Hairong Kuang via cutting)
23. HADOOP-715. Fix build.xml so that test logs are written in build directory, rather than in CWD.
    (Arun C Murthy via cutting)
24. HADOOP-538. Add support for building an optional native library, libhadoop.so, that improves the performance of zlib-based compression. To build this, specify -Dcompile.native to Ant.
    (Arun C Murthy via cutting)
25. HADOOP-610. Fix an problem when the DFS block size is configured to be smaller than the buffer size, typically only when debugging.
    (Milind Bhandarkar via cutting)
26. HADOOP-695. Fix a NullPointerException in contrib/streaming.
    (Hairong Kuang via cutting)
27. HADOOP-652. In DFS, when a file is deleted, the block count is now decremented.
    (Vladimir Krokhmalyov via cutting)
28. HADOOP-725. In DFS, optimize block placement algorithm, previously a performance bottleneck.
    (Milind Bhandarkar via cutting)
29. HADOOP-723. In MapReduce, fix a race condition during the shuffle, which resulted in FileNotFoundExceptions.
    (omalley via cutting)
30. HADOOP-447. In DFS, fix getBlockSize(Path) to work with relative paths.
    (Raghu Angadi via cutting)
31. HADOOP-733. Make exit codes in DFShell consistent and add a unit test.
    (Dhruba Borthakur via cutting)
32. HADOOP-709. Fix contrib/streaming to work with commands that contain control characters.
    (Dhruba Borthakur via cutting)
33. HADOOP-677. In IPC, permit a version header to be transmitted when connections are established. This will permit us to change the format of IPC requests back-compatibly in subsequent releases.
    (omalley via cutting)
34. HADOOP-699. Fix DFS web interface so that filesystem browsing works correctly, using the right port number. Also add support for sorting datanode list by various columns.
    (Raghu Angadi via cutting)
35. HADOOP-76. Implement speculative reduce. Now when a job is configured for speculative execution, both maps and reduces will execute speculatively. Reduce outputs are written to temporary location and moved to the final location when reduce is complete.
    (Sanjay Dahiya via cutting)
36. HADOOP-736. Roll back to Jetty 5.1.4, due to performance problems with Jetty 6.0.1.
37. HADOOP-739. Fix TestIPC to use different port number, making it more reliable.
    (Nigel Daley via cutting)
38. HADOOP-749. Fix a NullPointerException in jobfailures.jsp.
    (omalley via cutting)
39. HADOOP-747. Fix record serialization to work correctly when records are embedded in Maps.
    (Milind Bhandarkar via cutting)
40. HADOOP-698. Fix HDFS client not to retry the same datanode on read failures.
    (Milind Bhandarkar via cutting)
41. HADOOP-689. Add GenericWritable, to facilitate polymorphism in MapReduce, SequenceFile, etc.
    (Feng Jiang via cutting)
42. HADOOP-430. Stop datanode's HTTP server when registration with namenode fails.
    (Wendy Chien via cutting)
43. HADOOP-750. Fix a potential race condition during mapreduce shuffle.
    (omalley via cutting)
44. HADOOP-728. Fix contrib/streaming-related issues, including '-reducer NONE'.
    (Sanjay Dahiya via cutting)

### Release 0.8.0 - 2006-11-03

1. HADOOP-477. Extend contrib/streaming to scan the PATH environment variables when resolving executable program names.
   (Dhruba Borthakur via cutting)
2. HADOOP-583. In DFSClient, reduce the log level of re-connect attempts from 'info' to 'debug', so they are not normally shown.
   (Konstantin Shvachko via cutting)
3. HADOOP-498. Re-implement DFS integrity checker to run server-side, for much improved performance.
   (Milind Bhandarkar via cutting)
4. HADOOP-586. Use the jar name for otherwise un-named jobs.
   (Sanjay Dahiya via cutting)
5. HADOOP-514. Make DFS heartbeat interval configurable.
   (Milind Bhandarkar via cutting)
6. HADOOP-588. Fix logging and accounting of failed tasks.
   (Sanjay Dahiya via cutting)
7. HADOOP-462. Improve command line parsing in DFSShell, so that incorrect numbers of arguments result in informative errors rather than ArrayOutOfBoundsException.
   (Dhruba Borthakur via cutting)
8. HADOOP-561. Fix DFS so that one replica of each block is written locally, if possible. This was the intent, but there as a bug.
   (Dhruba Borthakur via cutting)
9. HADOOP-610. Fix TaskTracker to survive more exceptions, keeping tasks from becoming lost.
   (omalley via cutting)
10. HADOOP-625. Add a servlet to all http daemons that displays a stack dump, useful for debugging.
    (omalley via cutting)
11. HADOOP-554. Fix DFSShell to return -1 for errors.
    (Dhruba Borthakur via cutting)
12. HADOOP-626. Correct the documentation in the NNBench example code, and also remove a mistaken call there.
    (Nigel Daley via cutting)
13. HADOOP-634. Add missing license to many files.
    (Nigel Daley via cutting)
14. HADOOP-627. Fix some synchronization problems in MiniMRCluster that sometimes caused unit tests to fail.
    (Nigel Daley via cutting)
15. HADOOP-563. Improve the NameNode's lease policy so that leases are held for one hour without renewal (instead of one minute). However another attempt to create the same file will still succeed if the lease has not been renewed within a minute. This prevents communication or scheduling problems from causing a write to fail for up to an hour, barring some other process trying to create the same file.
    (Dhruba Borthakur via cutting)
16. HADOOP-635. In DFSShell, permit specification of multiple files as the source for file copy and move commands.
    (Dhruba Borthakur via cutting)
17. HADOOP-641. Change NameNode to request a fresh block report from a re-discovered DataNode, so that no-longer-needed replications are stopped promptly.
    (Konstantin Shvachko via cutting)
18. HADOOP-642. Change IPC client to specify an explicit connect timeout.
    (Konstantin Shvachko via cutting)
19. HADOOP-638. Fix an unsynchronized access to TaskTracker's internal state.
    (Nigel Daley via cutting)
20. HADOOP-624. Fix servlet path to stop a Jetty warning on startup.
    (omalley via cutting)
21. HADOOP-578. Failed tasks are no longer placed at the end of the task queue. This was originally done to work around other problems that have now been fixed. Re-executing failed tasks sooner causes buggy jobs to fail faster.
    (Sanjay Dahiya via cutting)
22. HADOOP-658. Update source file headers per Apache policy.
    (cutting)
23. HADOOP-636. Add MapFile & ArrayFile constructors which accept a Progressable, and pass it down to SequenceFile. This permits reduce tasks which use MapFile to still report progress while writing blocks to the filesystem.
    (cutting)
24. HADOOP-576. Enable contrib/streaming to use the file cache. Also extend the cache to permit symbolic links to cached items, rather than local file copies.
    (Mahadev Konar via cutting)
25. HADOOP-482. Fix unit tests to work when a cluster is running on the same machine, removing port conflicts.
    (Wendy Chien via cutting)
26. HADOOP-90. Permit dfs.name.dir to list multiple directories, where namenode data is to be replicated.
    (Milind Bhandarkar via cutting)
27. HADOOP-651. Fix DFSCk to correctly pass parameters to the servlet on the namenode.
    (Milind Bhandarkar via cutting)
28. HADOOP-553. Change main() routines of DataNode and NameNode to log exceptions rather than letting the JVM print them to standard error. Also, change the hadoop-daemon.sh script to rotate standard i/o log files.
    (Raghu Angadi via cutting)
29. HADOOP-399. Fix javadoc warnings.
    (Nigel Daley via cutting)
30. HADOOP-599. Fix web ui and command line to correctly report DFS filesystem size statistics. Also improve web layout.
    (Raghu Angadi via cutting)
31. HADOOP-660. Permit specification of junit test output format.
    (Nigel Daley via cutting)
32. HADOOP-663. Fix a few unit test issues.
    (Mahadev Konar via cutting)
33. HADOOP-664. Cause entire build to fail if libhdfs tests fail.
    (Nigel Daley via cutting)
34. HADOOP-633. Keep jobtracker from dying when job initialization throws exceptions. Also improve exception handling in a few other places and add more informative thread names.
    (omalley via cutting)
35. HADOOP-669. Fix a problem introduced by HADOOP-90 that can cause DFS to lose files.
    (Milind Bhandarkar via cutting)
36. HADOOP-373. Consistently check the value returned by FileSystem.mkdirs().
    (Wendy Chien via cutting)
37. HADOOP-670. Code cleanups in some DFS internals: use generic types, replace Vector with ArrayList, etc.
    (Konstantin Shvachko via cutting)
38. HADOOP-647. Permit map outputs to use a different compression type than the job output.
    (omalley via cutting)
39. HADOOP-671. Fix file cache to check for pre-existence before creating .
    (Mahadev Konar via cutting)
40. HADOOP-665. Extend many DFSShell commands to accept multiple arguments. Now commands like "ls", "rm", etc. will operate on multiple files.
    (Dhruba Borthakur via cutting)

### Release 0.7.2 - 2006-10-18

1. HADOOP-607. Fix a bug where classes included in job jars were not found by tasks.
   (Mahadev Konar via cutting)
2. HADOOP-609. Add a unit test that checks that classes in job jars can be found by tasks. Also modify unit tests to specify multiple local directories.
   (Mahadev Konar via cutting)

### Release 0.7.1 - 2006-10-11

1. HADOOP-593. Fix a NullPointerException in the JobTracker.
   (omalley via cutting)
2. HADOOP-592. Fix a NullPointerException in the IPC Server. Also consistently log when stale calls are discarded.
   (omalley via cutting)
3. HADOOP-594. Increase the DFS safe-mode threshold from .95 to .999, so that nearly all blocks must be reported before filesystem modifications are permitted.
   (Konstantin Shvachko via cutting)
4. HADOOP-598. Fix tasks to retry when reporting completion, so that a single RPC timeout won't fail a task.
   (omalley via cutting)
5. HADOOP-597. Fix TaskTracker to not discard map outputs for errors in transmitting them to reduce nodes.
   (omalley via cutting)

### Release 0.7.0 - 2006-10-06

1. HADOOP-243. Fix rounding in the display of task and job progress so that things are not shown to be 100% complete until they are in fact finished.
   (omalley via cutting)
2. HADOOP-438. Limit the length of absolute paths in DFS, since the file format used to store pathnames has some limitations.
   (Wendy Chien via cutting)
3. HADOOP-530. Improve error messages in SequenceFile when keys or values are of the wrong type.
   (Hairong Kuang via cutting)
4. HADOOP-288. Add a file caching system and use it in MapReduce to cache job jar files on slave nodes.
   (Mahadev Konar via cutting)
5. HADOOP-533. Fix unit test to not modify conf directory.
   (Hairong Kuang via cutting)
6. HADOOP-527. Permit specification of the local address that various Hadoop daemons should bind to.
   (Philippe Gassmann via cutting)
7. HADOOP-542. Updates to contrib/streaming: reformatted source code, on-the-fly merge sort, a fix for HADOOP-540, etc.
   (Michel Tourn via cutting)
8. HADOOP-545. Remove an unused config file parameter.
   (Philippe Gassmann via cutting)
9. HADOOP-548. Add an Ant property "test.output" to build.xml that causes test output to be logged to the console.
   (omalley via cutting)
10. HADOOP-261. Record an error message when map output is lost.
    (omalley via cutting)
11. HADOOP-293. Report the full list of task error messages in the web ui, not just the most recent.
    (omalley via cutting)
12. HADOOP-551. Restore JobClient's console printouts to only include a maximum of one update per one percent of progress.
    (omalley via cutting)
13. HADOOP-306. Add a "safe" mode to DFS. The name node enters this when less than a specified percentage of file data is complete. Currently safe mode is only used on startup, but eventually it will also be entered when datanodes disconnect and file data becomes incomplete. While in safe mode no filesystem modifications are permitted and block replication is inhibited.
    (Konstantin Shvachko via cutting)
14. HADOOP-431. Change 'dfs -rm' to not operate recursively and add a new command, 'dfs -rmr' which operates recursively.
    (Sameer Paranjpye via cutting)
15. HADOOP-263. Include timestamps for job transitions. The web interface now displays the start and end times of tasks and the start times of sorting and reducing for reduce tasks. Also, extend ObjectWritable to handle enums, so that they can be passed as RPC parameters.
    (Sanjay Dahiya via cutting)
16. HADOOP-556. Contrib/streaming: send keep-alive reports to task tracker every 10 seconds rather than every 100 records, to avoid task timeouts.
    (Michel Tourn via cutting)
17. HADOOP-547. Fix reduce tasks to ping tasktracker while copying data, rather than only between copies, avoiding task timeouts.
    (Sanjay Dahiya via cutting)
18. HADOOP-537. Fix src/c++/libhdfs build process to create files in build/, no longer modifying the source tree.
    (Arun C Murthy via cutting)
19. HADOOP-487. Throw a more informative exception for unknown RPC hosts.
    (Sameer Paranjpye via cutting)
20. HADOOP-559. Add file name globbing (pattern matching) support to the FileSystem API, and use it in DFSShell ('bin/hadoop dfs') commands.
    (Hairong Kuang via cutting)
21. HADOOP-508. Fix a bug in FSDataInputStream. Incorrect data was returned after seeking to a random location.
    (Milind Bhandarkar via cutting)
22. HADOOP-560. Add a "killed" task state. This can be used to distinguish kills from other failures. Task state has also been converted to use an enum type instead of an int, uncovering a bug elsewhere. The web interface is also updated to display killed tasks.
    (omalley via cutting)
23. HADOOP-423. Normalize Paths containing directories named "." and "..", using the standard, unix interpretation. Also add checks in DFS, prohibiting the use of "." or ".." as directory or file names.
    (Wendy Chien via cutting)
24. HADOOP-513. Replace map output handling with a servlet, rather than a JSP page. This fixes an issue where IllegalStateException's were logged, sets content-length correctly, and better handles some errors.
    (omalley via cutting)
25. HADOOP-552. Improved error checking when copying map output files to reduce nodes.
    (omalley via cutting)
26. HADOOP-566. Fix scripts to work correctly when accessed through relative symbolic links.
    (Lee Faris via cutting)
27. HADOOP-519. Add positioned read methods to FSInputStream. These permit one to read from a stream without moving its position, and can hence be performed by multiple threads at once on a single stream. Implement an optimized version for DFS and local FS.
    (Milind Bhandarkar via cutting)
28. HADOOP-522. Permit block compression with MapFile and SetFile. Since these formats are always sorted, block compression can provide a big advantage.
    (cutting)
29. HADOOP-567. Record version and revision information in builds. A package manifest is added to the generated jar file containing version information, and a VersionInfo utility is added that includes further information, including the build date and user, and the subversion revision and repository. A 'bin/hadoop version' comand is added to show this information, and it is also added to various web interfaces.
    (omalley via cutting)
30. HADOOP-568. Fix so that errors while initializing tasks on a tasktracker correctly report the task as failed to the jobtracker, so that it will be rescheduled.
    (omalley via cutting)
31. HADOOP-550. Disable automatic UTF-8 validation in Text. This permits, e.g., TextInputFormat to again operate on non-UTF-8 data.
    (Hairong and Mahadev via cutting)
32. HADOOP-343. Fix mapred copying so that a failed tasktracker doesn't cause other copies to slow.
    (Sameer Paranjpye via cutting)
33. HADOOP-239. Add a persistent job history mechanism, so that basic job statistics are not lost after 24 hours and/or when the jobtracker is restarted.
    (Sanjay Dahiya via cutting)
34. HADOOP-506. Ignore heartbeats from stale task trackers.
    (Sanjay Dahiya via cutting)
35. HADOOP-255. Discard stale, queued IPC calls. Do not process calls whose clients will likely time out before they receive a response. When the queue is full, new calls are now received and queued, and the oldest calls are discarded, so that, when servers get bogged down, they no longer develop a backlog on the socket. This should improve some DFS namenode failure modes.
    (omalley via cutting)
36. HADOOP-581. Fix datanode to not reset itself on communications errors with the namenode. If a request to the namenode fails, the datanode should retry, not restart. This reduces the load on the namenode, since restarts cause a resend of the block report.
    (omalley via cutting)

### Release 0.6.2 - 2006-09-18

1. HADOOP-532. Fix a bug reading value-compressed sequence files, where an exception was thrown reporting that the full value had not been read.
   (omalley via cutting)
2. HADOOP-534. Change the default value class in JobConf to be Text instead of the now-deprecated UTF8. This fixes the Grep example program, which was updated to use Text, but relies on this default.
   (Hairong Kuang via cutting)

### Release 0.6.1 - 2006-09-13

1. HADOOP-520. Fix a bug in libhdfs, where write failures were not correctly returning error codes.
   (Arun C Murthy via cutting)
2. HADOOP-523. Fix a NullPointerException when TextInputFormat is explicitly specified. Also add a test case for this.
   (omalley via cutting)
3. HADOOP-521. Fix another NullPointerException finding the ClassLoader when using libhdfs.
   (omalley via cutting)
4. HADOOP-526. Fix a NullPointerException when attempting to start two datanodes in the same directory.
   (Milind Bhandarkar via cutting)
5. HADOOP-529. Fix a NullPointerException when opening value-compressed sequence files generated by pre-0.6.0 Hadoop.
   (omalley via cutting)

### Release 0.6.0 - 2006-09-08

1. HADOOP-427. Replace some uses of DatanodeDescriptor in the DFS web UI code with DatanodeInfo, the preferred public class.
   (Devaraj Das via cutting)
2. HADOOP-426. Fix streaming contrib module to work correctly on Solaris. This was causing nightly builds to fail.
   (Michel Tourn via cutting)
3. HADOOP-400. Improvements to task assignment. Tasks are no longer re-run on nodes where they have failed (unless no other node is available). Also, tasks are better load-balanced among nodes.
   (omalley via cutting)
4. HADOOP-324. Fix datanode to not exit when a disk is full, but rather simply to fail writes.
   (Wendy Chien via cutting)
5. HADOOP-434. Change smallJobsBenchmark to use standard Hadoop scripts.
   (Sanjay Dahiya via cutting)
6. HADOOP-453. Fix a bug in Text.setCapacity().
   (siren via cutting)
7. HADOOP-450. Change so that input types are determined by the RecordReader rather than specified directly in the JobConf. This facilitates jobs with a variety of input types.

   WARNING: This contains incompatible API changes! The RecordReader interface has two new methods that all user-defined InputFormats must now define. Also, the values returned by TextInputFormat are no longer of class UTF8, but now of class Text.
8. HADOOP-436. Fix an error-handling bug in the web ui.
   (Devaraj Das via cutting)
9. HADOOP-455. Fix a bug in Text, where DEL was not permitted.
   (Hairong Kuang via cutting)
10. HADOOP-456. Change the DFS namenode to keep a persistent record of the set of known datanodes. This will be used to implement a "safe mode" where filesystem changes are prohibited when a critical percentage of the datanodes are unavailable.
    (Konstantin Shvachko via cutting)
11. HADOOP-322. Add a job control utility. This permits one to specify job interdependencies. Each job is submitted only after the jobs it depends on have successfully completed.
    (Runping Qi via cutting)
12. HADOOP-176. Fix a bug in IntWritable.Comparator.
    (Dick King via cutting)
13. HADOOP-421. Replace uses of String in recordio package with Text class, for improved handling of UTF-8 data.
    (Milind Bhandarkar via cutting)
14. HADOOP-464. Improved error message when job jar not found.
    (Michel Tourn via cutting)
15. HADOOP-469. Fix /bin/bash specifics that have crept into our /bin/sh scripts since HADOOP-352.
    (Jean-Baptiste Quenot via cutting)
16. HADOOP-468. Add HADOOP_NICENESS environment variable to set scheduling priority for daemons.
    (Vetle Roeim via cutting)
17. HADOOP-473. Fix TextInputFormat to correctly handle more EOL formats. Things now work correctly with CR, LF or CRLF.
    (Dennis Kubes & James White via cutting)
18. HADOOP-461. Make Java 1.5 an explicit requirement.
    (cutting)
19. HADOOP-54. Add block compression to SequenceFile. One may now specify that blocks of keys and values are compressed together, improving compression for small keys and values. SequenceFile.Writer's constructor is now deprecated and replaced with a factory method.
    (Arun C Murthy via cutting)
20. HADOOP-281. Prohibit DFS files that are also directories.
    (Wendy Chien via cutting)
21. HADOOP-486. Add the job username to JobStatus instances returned by JobClient.
    (Mahadev Konar via cutting)
22. HADOOP-437. contrib/streaming: Add support for gzipped inputs.
    (Michel Tourn via cutting)
23. HADOOP-463. Add variable expansion to config files. Configuration property values may now contain variable expressions. A variable is referenced with the syntax '${variable}'. Variables values are found first in the configuration, and then in Java system properties. The default configuration is modified so that temporary directories are now under ${hadoop.tmp.dir}, which is, by default, /tmp/hadoop-${user.name}.
    (Michel Tourn via cutting)
24. HADOOP-419. Fix a NullPointerException finding the ClassLoader when using libhdfs.
    (omalley via cutting)
25. HADOOP-460. Fix contrib/smallJobsBenchmark to use Text instead of UTF8.
    (Sanjay Dahiya via cutting)
26. HADOOP-196. Fix Configuration(Configuration) constructor to work correctly.
    (Sami Siren via cutting)
27. HADOOP-501. Fix Configuration.toString() to handle URL resources.
    (Thomas Friol via cutting)
28. HADOOP-499. Reduce the use of Strings in contrib/streaming, replacing them with Text for better performance.
    (Hairong Kuang via cutting)
29. HADOOP-64. Manage multiple volumes with a single DataNode. Previously DataNode would create a separate daemon per configured volume, each with its own connection to the NameNode. Now all volumes are handled by a single DataNode daemon, reducing the load on the NameNode.
    (Milind Bhandarkar via cutting)
30. HADOOP-424. Fix MapReduce so that jobs which generate zero splits do not fail.
    (Fr??d??ric Bertin via cutting)
31. HADOOP-408. Adjust some timeouts and remove some others so that unit tests run faster.
    (cutting)
32. HADOOP-507. Fix an IllegalAccessException in DFS.
    (omalley via cutting)
33. HADOOP-320. Fix so that checksum files are correctly copied when the destination of a file copy is a directory.
    (Hairong Kuang via cutting)
34. HADOOP-286. In DFSClient, avoid pinging the NameNode with renewLease() calls when no files are being written.
    (Konstantin Shvachko via cutting)
35. HADOOP-312. Close idle IPC connections. All IPC connections were cached forever. Now, after a connection has been idle for more than a configurable amount of time (one second by default), the connection is closed, conserving resources on both client and server.
    (Devaraj Das via cutting)
36. HADOOP-497. Permit the specification of the network interface and nameserver to be used when determining the local hostname advertised by datanodes and tasktrackers.
    (Lorenzo Thione via cutting)
37. HADOOP-441. Add a compression codec API and extend SequenceFile to use it. This will permit the use of alternate compression codecs in SequenceFile.
    (Arun C Murthy via cutting)
38. HADOOP-483. Improvements to libhdfs build and documentation.
    (Arun C Murthy via cutting)
39. HADOOP-458. Fix a memory corruption bug in libhdfs.
    (Arun C Murthy via cutting)
40. HADOOP-517. Fix a contrib/streaming bug in end-of-line detection.
    (Hairong Kuang via cutting)
41. HADOOP-474. Add CompressionCodecFactory, and use it in TextInputFormat and TextOutputFormat. Compressed input files are automatically decompressed when they have the correct extension. Output files will, when output compression is specified, be generated with an approprate extension. Also add a gzip codec and fix problems with UTF8 text inputs.
    (omalley via cutting)

### Release 0.5.0 - 2006-08-04

1. HADOOP-352. Fix shell scripts to use /bin/sh instead of /bin/bash, for better portability.
   (Jean-Baptiste Quenot via cutting)
2. HADOOP-313. Permit task state to be saved so that single tasks may be manually re-executed when debugging.
   (omalley via cutting)
3. HADOOP-339. Add method to JobClient API listing jobs that are not yet complete, i.e., that are queued or running.
   (Mahadev Konar via cutting)
4. HADOOP-355. Updates to the streaming contrib module, including API fixes, making reduce optional, and adding an input type for StreamSequenceRecordReader.
   (Michel Tourn via cutting)
5. HADOOP-358. Fix a NPE bug in Path.equals().
   (Fr??d??ric Bertin via cutting)
6. HADOOP-327. Fix ToolBase to not call System.exit() when exceptions are thrown.
   (Hairong Kuang via cutting)
7. HADOOP-359. Permit map output to be compressed.
   (omalley via cutting)
8. HADOOP-341. Permit input URI to CopyFiles to use the HTTP protocol. This lets one, e.g., more easily copy log files into DFS.
   (Arun C Murthy via cutting)
9. HADOOP-361. Remove unix dependencies from streaming contrib module tests, making them pure java.
   (Michel Tourn via cutting)
10. HADOOP-354. Make public methods to stop DFS daemons.
    (Barry Kaplan via cutting)
11. HADOOP-252. Add versioning to RPC protocols.
    (Milind Bhandarkar via cutting)
12. HADOOP-356. Add contrib to "compile" and "test" build targets, so that this code is better maintained.
    (Michel Tourn via cutting)
13. HADOOP-307. Add smallJobsBenchmark contrib module. This runs lots of small jobs, in order to determine per-task overheads.
    (Sanjay Dahiya via cutting)
14. HADOOP-342. Add a tool for log analysis: Logalyzer.
    (Arun C Murthy via cutting)
15. HADOOP-347. Add web-based browsing of DFS content. The namenode redirects browsing requests to datanodes. Content requests are redirected to datanodes where the data is local when possible.
    (Devaraj Das via cutting)
16. HADOOP-351. Make Hadoop IPC kernel independent of Jetty.
    (Devaraj Das via cutting)
17. HADOOP-237. Add metric reporting to DFS and MapReduce. With only minor configuration changes, one can now monitor many Hadoop system statistics using Ganglia or other monitoring systems.
    (Milind Bhandarkar via cutting)
18. HADOOP-376. Fix datanode's HTTP server to scan for a free port.
    (omalley via cutting)
19. HADOOP-260. Add --config option to shell scripts, specifying an alternate configuration directory.
    (Milind Bhandarkar via cutting)
20. HADOOP-381. Permit developers to save the temporary files for tasks whose names match a regular expression, to facilliate debugging.
    (omalley via cutting)
21. HADOOP-344. Fix some Windows-related problems with DF.
    (Konstantin Shvachko via cutting)
22. HADOOP-380. Fix reduce tasks to poll less frequently for map outputs.
    (Mahadev Konar via cutting)
23. HADOOP-321. Refactor DatanodeInfo, in preparation for HADOOP-306.
    (Konstantin Shvachko & omalley via cutting)
24. HADOOP-385. Fix some bugs in record io code generation.
    (Milind Bhandarkar via cutting)
25. HADOOP-302. Add new Text class to replace UTF8, removing limitations of that class. Also refactor utility methods for writing zero-compressed integers (VInts and VLongs).
    (Hairong Kuang via cutting)
26. HADOOP-335. Refactor DFS namespace/transaction logging in namenode.
    (Konstantin Shvachko via cutting)
27. HADOOP-375. Fix handling of the datanode HTTP daemon's port so that multiple datanode's can be run on a single host.
    (Devaraj Das via cutting)
28. HADOOP-386. When removing excess DFS block replicas, remove those on nodes with the least free space first.
    (Johan Oskarson via cutting)
29. HADOOP-389. Fix intermittent failures of mapreduce unit tests. Also fix some build dependencies.
    (Mahadev & Konstantin via cutting)
30. HADOOP-362. Fix a problem where jobs hang when status messages are recieved out-of-order.
    (omalley via cutting)
31. HADOOP-394. Change order of DFS shutdown in unit tests to minimize errors logged.
    (Konstantin Shvachko via cutting)
32. HADOOP-396. Make DatanodeID implement Writable.
    (Konstantin Shvachko via cutting)
33. HADOOP-377. Permit one to add URL resources to a Configuration.
    (Jean-Baptiste Quenot via cutting)
34. HADOOP-345. Permit iteration over Configuration key/value pairs.
    (Michel Tourn via cutting)
35. HADOOP-409. Streaming contrib module: make configuration properties available to commands as environment variables.
    (Michel Tourn via cutting)
36. HADOOP-369. Add -getmerge option to dfs command that appends all files in a directory into a single local file.
    (Johan Oskarson via cutting)
37. HADOOP-410. Replace some TreeMaps with HashMaps in DFS, for a 17% performance improvement.
    (Milind Bhandarkar via cutting)
38. HADOOP-411. Add unit tests for command line parser.
    (Hairong Kuang via cutting)
39. HADOOP-412. Add MapReduce input formats that support filtering of SequenceFile data, including sampling and regex matching. Also, move JobConf.newInstance() to a new utility class.
    (Hairong Kuang via cutting)
40. HADOOP-226. Fix fsck command to properly consider replication counts, now that these can vary per file.
    (Bryan Pendleton via cutting)
41. HADOOP-425. Add a Python MapReduce example, using Jython.
    (omalley via cutting)

### Release 0.4.0 - 2006-06-28

1. HADOOP-298. Improved progress reports for CopyFiles utility, the distributed file copier.
   (omalley via cutting)
2. HADOOP-299. Fix the task tracker, permitting multiple jobs to more easily execute at the same time.
   (omalley via cutting)
3. HADOOP-250. Add an HTTP user interface to the namenode, running on port 50070.
   (Devaraj Das via cutting)
4. HADOOP-123. Add MapReduce unit tests that run a jobtracker and tasktracker, greatly increasing code coverage.
   (Milind Bhandarkar via cutting)
5. HADOOP-271. Add links from jobtracker's web ui to tasktracker's web ui. Also attempt to log a thread dump of child processes before they're killed.
   (omalley via cutting)
6. HADOOP-210. Change RPC server to use a selector instead of a thread per connection. This should make it easier to scale to larger clusters. Note that this incompatibly changes the RPC protocol: clients and servers must both be upgraded to the new version to ensure correct operation.
   (Devaraj Das via cutting)
7. HADOOP-311. Change DFS client to retry failed reads, so that a single read failure will not alone cause failure of a task.
   (omalley via cutting)
8. HADOOP-314. Remove the "append" phase when reducing. Map output files are now directly passed to the sorter, without first appending them into a single file. Now, the first third of reduce progress is "copy" (transferring map output to reduce nodes), the middle third is "sort" (sorting map output) and the last third is "reduce" (generating output). Long-term, the "sort" phase will also be removed.
   (omalley via cutting)
9. HADOOP-316. Fix a potential deadlock in the jobtracker.
   (omalley via cutting)
10. HADOOP-319. Fix FileSystem.close() to remove the FileSystem instance from the cache.
    (Hairong Kuang via cutting)
11. HADOOP-135. Fix potential deadlock in JobTracker by acquiring locks in a consistent order.
    (omalley via cutting)
12. HADOOP-278. Check for existence of input directories before starting MapReduce jobs, making it easier to debug this common error.
    (omalley via cutting)
13. HADOOP-304. Improve error message for UnregisterdDatanodeException to include expected node name.
    (Konstantin Shvachko via cutting)
14. HADOOP-305. Fix TaskTracker to ask for new tasks as soon as a task is finished, rather than waiting for the next heartbeat. This improves performance when tasks are short.
    (Mahadev Konar via cutting)
15. HADOOP-59. Add support for generic command line options. One may now specify the filesystem (-fs), the MapReduce jobtracker (-jt), a config file (-conf) or any configuration property (-D). The "dfs", "fsck", "job", and "distcp" commands currently support this, with more to be added.
    (Hairong Kuang via cutting)
16. HADOOP-296. Permit specification of the amount of reserved space on a DFS datanode. One may specify both the percentage free and the number of bytes.
    (Johan Oskarson via cutting)
17. HADOOP-325. Fix a problem initializing RPC parameter classes, and remove the workaround used to initialize classes.
    (omalley via cutting)
18. HADOOP-328. Add an option to the "distcp" command to ignore read errors while copying.
    (omalley via cutting)
19. HADOOP-27. Don't allocate tasks to trackers whose local free space is too low.
    (Johan Oskarson via cutting)
20. HADOOP-318. Keep slow DFS output from causing task timeouts. This incompatibly changes some public interfaces, adding a parameter to OutputFormat.getRecordWriter() and the new method Reporter.progress(), but it makes lots of tasks succeed that were previously failing.
    (Milind Bhandarkar via cutting)

### Release 0.3.2 - 2006-06-09

1. HADOOP-275. Update the streaming contrib module to use log4j for its logging.
   (Michel Tourn via cutting)
2. HADOOP-279. Provide defaults for log4j logging parameters, so that things still work reasonably when Hadoop-specific system properties are not provided.
   (omalley via cutting)
3. HADOOP-280. Fix a typo in AllTestDriver which caused the wrong test to be run when "DistributedFSCheck" was specified.
   (Konstantin Shvachko via cutting)
4. HADOOP-240. DFS's mkdirs() implementation no longer logs a warning when the directory already exists.
   (Hairong Kuang via cutting)
5. HADOOP-285. Fix DFS datanodes to be able to re-join the cluster after the connection to the namenode is lost.
   (omalley via cutting)
6. HADOOP-277. Fix a race condition when creating directories.
   (Sameer Paranjpye via cutting)
7. HADOOP-289. Improved exception handling in DFS datanode.
   (Konstantin Shvachko via cutting)
8. HADOOP-292. Fix client-side logging to go to standard error rather than standard output, so that it can be distinguished from application output.
   (omalley via cutting)
9. HADOOP-294. Fixed bug where conditions for retrying after errors in the DFS client were reversed.
   (omalley via cutting)

### Release 0.3.1 - 2006-06-05

1. HADOOP-272. Fix a bug in bin/hadoop setting log parameters.
   (omalley & cutting)
2. HADOOP-274. Change applications to log to standard output rather than to a rolling log file like daemons.
   (omalley via cutting)
3. HADOOP-262. Fix reduce tasks to report progress while they're waiting for map outputs, so that they do not time out.
   (Mahadev Konar via cutting)
4. HADOOP-245 and HADOOP-246. Improvements to record io package.
   (Mahadev Konar via cutting)
5. HADOOP-276. Add logging config files to jar file so that they're always found.
   (omalley via cutting)

### Release 0.3.0 - 2006-06-02

1. HADOOP-208. Enhance MapReduce web interface, adding new pages for failed tasks, and tasktrackers.
   (omalley via cutting)
2. HADOOP-204. Tweaks to metrics package.
   (David Bowen via cutting)
3. HADOOP-209. Add a MapReduce-based file copier. This will copy files within or between file systems in parallel.
   (Milind Bhandarkar via cutting)
4. HADOOP-146. Fix DFS to check when randomly generating a new block id that no existing blocks already have that id.
   (Milind Bhandarkar via cutting)
5. HADOOP-180. Make a daemon thread that does the actual task clean ups, so that the main offerService thread in the taskTracker doesn't get stuck and miss his heartbeat window. This was killing many task trackers as big jobs finished (300+ tasks / node).
   (omalley via cutting)
6. HADOOP-200. Avoid transmitting entire list of map task names to reduce tasks. Instead just transmit the number of map tasks and henceforth refer to them by number when collecting map output.
   (omalley via cutting)
7. HADOOP-219. Fix a NullPointerException when handling a checksum exception under SequenceFile.Sorter.sort().
   (cutting & stack)
8. HADOOP-212. Permit alteration of the file block size in DFS. The default block size for new files may now be specified in the configuration with the dfs.block.size property. The block size may also be specified when files are opened.
   (omalley via cutting)
9. HADOOP-218. Avoid accessing configuration while looping through tasks in JobTracker.
   (Mahadev Konar via cutting)
10. HADOOP-161. Add hashCode() method to DFS's Block.
    (Milind Bhandarkar via cutting)
11. HADOOP-115. Map output types may now be specified. These are also used as reduce input types, thus permitting reduce input types to differ from reduce output types.
    (Runping Qi via cutting)
12. HADOOP-216. Add task progress to task status page.
    (Bryan Pendelton via cutting)
13. HADOOP-233. Add web server to task tracker that shows running tasks and logs. Also add log access to job tracker web interface.
    (omalley via cutting)
14. HADOOP-205. Incorporate pending tasks into tasktracker load calculations.
    (Mahadev Konar via cutting)
15. HADOOP-247. Fix sort progress to better handle exceptions.
    (Mahadev Konar via cutting)
16. HADOOP-195. Improve performance of the transfer of map outputs to reduce nodes by performing multiple transfers in parallel, each on a separate socket.
    (Sameer Paranjpye via cutting)
17. HADOOP-251. Fix task processes to be tolerant of failed progress reports to their parent process.
    (omalley via cutting)
18. HADOOP-325. Improve the FileNotFound exceptions thrown by LocalFileSystem to include the name of the file.
    (Benjamin Reed via cutting)
19. HADOOP-254. Use HTTP to transfer map output data to reduce nodes. This, together with HADOOP-195, greatly improves the performance of these transfers.
    (omalley via cutting)
20. HADOOP-163. Cause datanodes that\ are unable to either read or write data to exit, so that the namenode will no longer target them for new blocks and will replicate their data on other nodes.
    (Hairong Kuang via cutting)
21. HADOOP-222. Add a -setrep option to the dfs commands that alters file replication levels.
    (Johan Oskarson via cutting)
22. HADOOP-75. In DFS, only check for a complete file when the file is closed, rather than as each block is written.
    (Milind Bhandarkar via cutting)
23. HADOOP-124. Change DFS so that datanodes are identified by a persistent ID rather than by host and port. This solves a number of filesystem integrity problems, when, e.g., datanodes are restarted.
    (Konstantin Shvachko via cutting)
24. HADOOP-256. Add a C API for DFS.
    (Arun C Murthy via cutting)
25. HADOOP-211. Switch to use the Jakarta Commons logging internally, configured to use log4j by default.
    (Arun C Murthy and cutting)
26. HADOOP-265. Tasktracker now fails to start if it does not have a writable local directory for temporary files. In this case, it logs a message to the JobTracker and exits.
    (Hairong Kuang via cutting)
27. HADOOP-270. Fix potential deadlock in datanode shutdown.
    (Hairong Kuang via cutting)

### Release 0.2.1 - 2006-05-12

1. HADOOP-199. Fix reduce progress (broken by HADOOP-182).
   (omalley via cutting)
2. HADOOP-201. Fix 'bin/hadoop dfs -report'.
   (cutting)
3. HADOOP-207. Fix JDK 1.4 incompatibility introduced by HADOOP-96. System.getenv() does not work in JDK 1.4.
   (Hairong Kuang via cutting)

### Release 0.2.0 - 2006-05-05

1. Fix HADOOP-126. 'bin/hadoop dfs -cp' now correctly copies .crc files.
   (Konstantin Shvachko via cutting)
2. Fix HADOOP-51. Change DFS to support per-file replication counts.
   (Konstantin Shvachko via cutting)
3. Fix HADOOP-131. Add scripts to start/stop dfs and mapred daemons. Use these in start/stop-all scripts.
   (Chris Mattmann via cutting)
4. Stop using ssh options by default that are not yet in widely used versions of ssh. Folks can still enable their use by uncommenting a line in conf/hadoop-env.sh.
   (cutting)
5. Fix HADOOP-92. Show information about all attempts to run each task in the web ui.
   (Mahadev konar via cutting)
6. Fix HADOOP-128. Improved DFS error handling.
   (Owen O'Malley via cutting)
7. Fix HADOOP-129. Replace uses of java.io.File with new class named Path. This fixes bugs where java.io.File methods were called directly when FileSystem methods were desired, and reduces the likelihood of such bugs in the future. It also makes the handling of pathnames more consistent between local and dfs FileSystems and between Windows and Unix. java.io.File-based methods are still available for back-compatibility, but are deprecated and will be removed once 0.2 is released.
   (cutting)
8. Change dfs.data.dir and mapred.local.dir to be comma-separated lists of directories, no longer be space-separated. This fixes several bugs on Windows.
   (cutting)
9. Fix HADOOP-144. Use mapred task id for dfs client id, to facilitate debugging.
   (omalley via cutting)
10. Fix HADOOP-143. Do not line-wrap stack-traces in web ui.
    (omalley via cutting)
11. Fix HADOOP-118. In DFS, improve clean up of abandoned file creations.
    (omalley via cutting)
12. Fix HADOOP-138. Stop multiple tasks in a single heartbeat, rather than one per heartbeat.
    (Stefan via cutting)
13. Fix HADOOP-139. Remove a potential deadlock in LocalFileSystem.lock().
    (Igor Bolotin via cutting)
14. Fix HADOOP-134. Don't hang jobs when the tasktracker is misconfigured to use an un-writable local directory.
    (omalley via cutting)
15. Fix HADOOP-115. Correct an error message.
    (Stack via cutting)
16. Fix HADOOP-133. Retry pings from child to parent, in case of (local) communcation problems. Also log exit status, so that one can distinguish patricide from other deaths.
    (omalley via cutting)
17. Fix HADOOP-142. Avoid re-running a task on a host where it has previously failed.
    (omalley via cutting)
18. Fix HADOOP-148. Maintain a task failure count for each tasktracker and display it in the web ui.
    (omalley via cutting)
19. Fix HADOOP-151. Close a potential socket leak, where new IPC connection pools were created per configuration instance that RPCs use. Now a global RPC connection pool is used again, as originally intended.
    (cutting)
20. Fix HADOOP-69. Don't throw a NullPointerException when getting hints for non-existing file split.
    (Bryan Pendelton via cutting)
21. Fix HADOOP-157. When a task that writes dfs files (e.g., a reduce task) failed and was retried, it would fail again and again, eventually failing the job. The problem was that dfs did not yet know that the failed task had abandoned the files, and would not yet let another task create files with the same names. Dfs now retries when creating a file long enough for locks on abandoned files to expire.
    (omalley via cutting)
22. Fix HADOOP-150. Improved task names that include job names.
    (omalley via cutting)
23. Fix HADOOP-162. Fix ConcurrentModificationException when releasing file locks.
    (omalley via cutting)
24. Fix HADOOP-132. Initial check-in of new Metrics API, including implementations for writing metric data to a file and for sending it to Ganglia.
    (David Bowen via cutting)
25. Fix HADOOP-160. Remove some uneeded synchronization around time-consuming operations in the TaskTracker.
    (omalley via cutting)
26. Fix HADOOP-166. RPCs failed when passed subclasses of a declared parameter type. This is fixed by changing ObjectWritable to store both the declared type and the instance type for Writables. Note that this incompatibly changes the format of ObjectWritable and will render unreadable any ObjectWritables stored in files. Nutch only uses ObjectWritable in intermediate files, so this should not be a problem for Nutch.
    (Stefan & cutting)
27. Fix HADOOP-168. MapReduce RPC protocol methods should all declare IOException, so that timeouts are handled appropriately.
    (omalley via cutting)
28. Fix HADOOP-169. Don't fail a reduce task if a call to the jobtracker to locate map outputs fails.
    (omalley via cutting)
29. Fix HADOOP-170. Permit FileSystem clients to examine and modify the replication count of individual files. Also fix a few replication-related bugs.
    (Konstantin Shvachko via cutting)
30. Permit specification of a higher replication levels for job submission files (job.xml and job.jar). This helps with large clusters, since these files are read by every node.
    (cutting)
31. HADOOP-173. Optimize allocation of tasks with local data.
    (cutting)
32. HADOOP-167. Reduce number of Configurations and JobConf's created.
    (omalley via cutting)
33. NUTCH-256. Change FileSystem#createNewFile() to create a .crc file. The lack of a .crc file was causing warnings.
    (cutting)
34. HADOOP-174. Change JobClient to not abort job until it has failed to contact the job tracker for five attempts, not just one as before.
    (omalley via cutting)
35. HADOOP-177. Change MapReduce web interface to page through tasks. Previously, when jobs had more than a few thousand tasks they could crash web browsers.
    (Mahadev Konar via cutting)
36. HADOOP-178. In DFS, piggyback blockwork requests from datanodes on heartbeat responses from namenode. This reduces the volume of RPC traffic. Also move startup delay in blockwork from datanode to namenode. This fixes a problem where restarting the namenode triggered a lot of uneeded replication.
    (Hairong Kuang via cutting)
37. HADOOP-183. If the DFS namenode is restarted with different minimum and/or maximum replication counts, existing files' replication counts are now automatically adjusted to be within the newly configured bounds.
    (Hairong Kuang via cutting)
38. HADOOP-186. Better error handling in TaskTracker's top-level loop. Also improve calculation of time to send next heartbeat.
    (omalley via cutting)
39. HADOOP-187. Add two MapReduce examples/benchmarks. One creates files containing random data. The second sorts the output of the first.
    (omalley via cutting)
40. HADOOP-185. Fix so that, when a task tracker times out making the RPC asking for a new task to run, the job tracker does not think that it is actually running the task returned.
    (omalley via cutting)
41. HADOOP-190. If a child process hangs after it has reported completion, its output should not be lost.
    (Stack via cutting)
42. HADOOP-184. Re-structure some test code to better support testing on a cluster.
    (Mahadev Konar via cutting)
43. HADOOP-191 Add streaming package, Hadoop's first contrib module. This permits folks to easily submit MapReduce jobs whose map and reduce functions are implemented by shell commands. Use 'bin/hadoop jar build/hadoop-streaming.jar' to get details.
    (Michel Tourn via cutting)
44. HADOOP-189. Fix MapReduce in standalone configuration to correctly handle job jar files that contain a lib directory with nested jar files.
    (cutting)
45. HADOOP-65. Initial version of record I/O framework that enables the specification of record types and generates marshalling code in both Java and C++. Generated Java code implements WritableComparable, but is not yet otherwise used by Hadoop.
    (Milind Bhandarkar via cutting)
46. HADOOP-193. Add a MapReduce-based FileSystem benchmark.
    (Konstantin Shvachko via cutting)
47. HADOOP-194. Add a MapReduce-based FileSystem checker. This reads every block in every file in the filesystem.
    (Konstantin Shvachko via cutting)
48. HADOOP-182. Fix so that lost task trackers to not change the status of reduce tasks or completed jobs. Also fixes the progress meter so that failed tasks are subtracted.
    (omalley via cutting)
49. HADOOP-96. Logging improvements. Log files are now separate from standard output and standard error files. Logs are now rolled. Logging of all DFS state changes can be enabled, to facilitate debugging.
    (Hairong Kuang via cutting)

### Release 0.1.1 - 2006-04-08

1. Added CHANGES.txt, logging all significant changes to Hadoop.
   (cutting)
2. Fix MapReduceBase.close() to throw IOException, as declared in the Closeable interface. This permits subclasses which override this method to throw that exception.
   (cutting)
3. Fix HADOOP-117. Pathnames were mistakenly transposed in JobConf.getLocalFile() causing many mapred temporary files to not be removed.
   (Raghavendra Prabhu via cutting)
4. Fix HADOOP-116. Clean up job submission files when jobs complete.
   (cutting)
5. Fix HADOOP-125. Fix handling of absolute paths on Windows
   (cutting)

### Release 0.1.0 - 2006-04-01

1. The first release of Hadoop.