org.apache.druid.indexer

Class DeterminePartitionsJob

java.lang.Object

org.apache.druid.indexer.DeterminePartitionsJob

All Implemented Interfaces:

Jobby

public class DeterminePartitionsJob
extends Object
implements Jobby

Determines appropriate ShardSpecs for a job by determining whether or not partitioning is necessary, and if so, choosing the best dimension that satisfies the criteria:

• Must have exactly one value per row.
• Must not generate oversized partitions. A dimension with N rows having the same value will necessarily put all those rows in the same partition, and that partition may be much larger than the target size.

"Best" means a very high cardinality dimension, or, if none exist, the dimension that minimizes variation of segment size relative to the target.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	DeterminePartitionsJob.DeterminePartitionsDimSelectionAssumeGroupedMapper This DimSelection mapper runs on raw input data that we assume has already been grouped.
static class	DeterminePartitionsJob.DeterminePartitionsDimSelectionCombiner
static class	DeterminePartitionsJob.DeterminePartitionsDimSelectionOutputFormat
static class	DeterminePartitionsJob.DeterminePartitionsDimSelectionPartitioner
static class	DeterminePartitionsJob.DeterminePartitionsDimSelectionPostGroupByMapper This DimSelection mapper runs on data generated by our GroupBy job.
static class	DeterminePartitionsJob.DeterminePartitionsDimSelectionReducer
static class	DeterminePartitionsJob.DeterminePartitionsGroupByMapper
static class	DeterminePartitionsJob.DeterminePartitionsGroupByReducer

Method Summary

Modifier and Type	Method and Description
String	getErrorMessage()
Map<String,Object>	getStats()
boolean	run()

Methods inherited from class java.lang.Object

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

Method Detail

run

public boolean run()

Specified by:

run in interface Jobby

getStats

public Map<String,Object> getStats()

Specified by:

getStats in interface Jobby

getErrorMessage

@Nullable
public String getErrorMessage()

Specified by:

getErrorMessage in interface Jobby