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

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

All Implemented Interfaces:

Transform

public class BucketingSortingReduceSinkOptimizer
extends Object
implements Transform

This transformation does optimization for enforcing bucketing and sorting. For a query of the form: insert overwrite table T1 select * from T2; where T1 and T2 are bucketized/sorted on the same keys, we don't need a reducer to enforce bucketing and sorting. It also optimizes queries of the form: insert overwrite table T1 select * from T1 join T2 on T1.key = T2.key where T1, T2 and T3 are bucketized/sorted on the same key 'key', we don't need a reducer to enforce bucketing and sorting

Nested Class Summary

class

BucketingSortingReduceSinkOptimizer.BucketSortReduceSinkProcessor BucketSortReduceSinkProcessor.

Constructor Summary

BucketingSortingReduceSinkOptimizer()

Method Summary

ParseContext

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

Methods inherited from class java.lang.Object

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

Constructor Detail

BucketingSortingReduceSinkOptimizer

public BucketingSortingReduceSinkOptimizer()

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