org.apache.hadoop.hive.ql.optimizer
Class ReduceSinkDeDuplication

java.lang.Object
  org.apache.hadoop.hive.ql.optimizer.ReduceSinkDeDuplication

All Implemented Interfaces:

Transform

public class ReduceSinkDeDuplication
extends Object
implements Transform

If two reducer sink operators share the same partition/sort columns, we should merge them. This should happen after map join optimization because map join optimization will remove reduce sink operators.

Field Summary

protected ParseContext

pGraphContext

Constructor Summary

ReduceSinkDeDuplication()

Method Summary

ParseContext

transform(ParseContext pctx) All transformation steps implement this interface.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

pGraphContext

protected ParseContext pGraphContext

Constructor Detail

ReduceSinkDeDuplication

public ReduceSinkDeDuplication()

Method Detail

transform

public ParseContext transform(ParseContext pctx)
                       throws SemanticException

Description copied from interface: Transform

All transformation steps implement this interface.

Specified by:

transform in interface Transform

Parameters:

pctx - input parse context

Returns:

ParseContext

Throws:

SemanticException