org.apache.hadoop.hive.ql.optimizer

Class SortedDynPartitionOptimizer

java.lang.Object

org.apache.hadoop.hive.ql.optimizer.Transform

org.apache.hadoop.hive.ql.optimizer.SortedDynPartitionOptimizer

public class SortedDynPartitionOptimizer
extends Transform

When dynamic partitioning (with or without bucketing and sorting) is enabled, this optimization sorts the records on partition, bucket and sort columns respectively before inserting records into the destination table. This enables reducers to keep only one record writer all the time thereby reducing the the memory pressure on the reducers.

Field Summary

Fields

Modifier and Type	Field and Description
static String	BUCKET_NUMBER_COL_NAME

Constructor Summary

Constructors

Constructor and Description
SortedDynPartitionOptimizer()

Method Summary

Modifier and Type	Method and Description
ParseContext	transform(ParseContext pCtx) All transformation steps implement this interface.

Methods inherited from class org.apache.hadoop.hive.ql.optimizer.Transform

beginPerfLogging, endPerfLogging, endPerfLogging

Methods inherited from class java.lang.Object

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

Field Detail

BUCKET_NUMBER_COL_NAME

public static final String BUCKET_NUMBER_COL_NAME

See Also:

Constant Field Values

Constructor Detail

SortedDynPartitionOptimizer

public SortedDynPartitionOptimizer()

Method Detail

transform

public ParseContext transform(ParseContext pCtx)
                       throws SemanticException

Description copied from class: Transform

All transformation steps implement this interface.

Specified by:

transform in class Transform

Parameters:

pCtx - input parse context

Returns:

ParseContext

Throws:

SemanticException