org.apache.hadoop.hive.ql.ppd
Class ExprWalkerProcFactory

java.lang.Object
  extended by org.apache.hadoop.hive.ql.ppd.ExprWalkerProcFactory

public class ExprWalkerProcFactory
extends Object

Expression factory for predicate pushdown processing. Each processor determines whether the expression is a possible candidate for predicate pushdown optimization for the given operator


Nested Class Summary
static class ExprWalkerProcFactory.ColumnExprProcessor
           
static class ExprWalkerProcFactory.DefaultExprProcessor
          For constants and null expressions
static class ExprWalkerProcFactory.FieldExprProcessor
           
static class ExprWalkerProcFactory.FuncExprProcessor
          If all children are candidates and refer only to one table alias then this expr is a candidate else it is not a candidate but its children could be final candidates
static class ExprWalkerProcFactory.GenericFuncExprProcessor
          If all children are candidates and refer only to one table alias then this expr is a candidate else it is not a candidate but its children could be final candidates
 
Constructor Summary
ExprWalkerProcFactory()
           
 
Method Summary
static ExprWalkerInfo extractPushdownPreds(OpWalkerInfo opContext, Operator<? extends Serializable> op, exprNodeDesc pred)
           
static ExprWalkerInfo extractPushdownPreds(OpWalkerInfo opContext, Operator<? extends Serializable> op, List<exprNodeDesc> preds)
          Extracts pushdown predicates from the given list of predicate expression
static NodeProcessor getColumnProcessor()
           
static NodeProcessor getDefaultExprProcessor()
           
static NodeProcessor getFuncProcessor()
           
static NodeProcessor getGenericFuncProcessor()
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ExprWalkerProcFactory

public ExprWalkerProcFactory()
Method Detail

getDefaultExprProcessor

public static NodeProcessor getDefaultExprProcessor()

getFuncProcessor

public static NodeProcessor getFuncProcessor()

getGenericFuncProcessor

public static NodeProcessor getGenericFuncProcessor()

getColumnProcessor

public static NodeProcessor getColumnProcessor()

extractPushdownPreds

public static ExprWalkerInfo extractPushdownPreds(OpWalkerInfo opContext,
                                                  Operator<? extends Serializable> op,
                                                  exprNodeDesc pred)
                                           throws SemanticException
Throws:
SemanticException

extractPushdownPreds

public static ExprWalkerInfo extractPushdownPreds(OpWalkerInfo opContext,
                                                  Operator<? extends Serializable> op,
                                                  List<exprNodeDesc> preds)
                                           throws SemanticException
Extracts pushdown predicates from the given list of predicate expression

Parameters:
opContext - operator context used for resolving column references
op - operator of the predicates being processed
preds -
Returns:
The expression walker information
Throws:
SemanticException


Copyright © 2009 The Apache Software Foundation