Package org.apache.lucene.misc.index

Class BPReorderingMergePolicy

java.lang.Object

org.apache.lucene.index.MergePolicy

org.apache.lucene.index.FilterMergePolicy

org.apache.lucene.misc.index.BPReorderingMergePolicy

All Implemented Interfaces:

Unwrappable<MergePolicy>

public final class BPReorderingMergePolicy
extends FilterMergePolicy

A merge policy that reorders merged segments according to a BPIndexReorderer. When reordering doesn't have enough RAM, it simply skips reordering in order not to fail the merge. So make sure to give enough RAM to your BPIndexReorderer via BPIndexReorderer.setRAMBudgetMB(double).

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.index.MergePolicy

MergePolicy.MergeAbortedException, MergePolicy.MergeContext, MergePolicy.MergeException, MergePolicy.MergeSpecification, MergePolicy.OneMerge, MergePolicy.OneMergeProgress

Field Summary

Fields inherited from class org.apache.lucene.index.FilterMergePolicy

in

Fields inherited from class org.apache.lucene.index.MergePolicy

DEFAULT_MAX_CFS_SEGMENT_SIZE, DEFAULT_NO_CFS_RATIO, maxCFSSegmentSize, noCFSRatio

Constructor Summary

Constructors

Constructor	Description
BPReorderingMergePolicy(MergePolicy in, BPIndexReorderer reorderer)	Sole constructor.

Method Summary

Modifier and Type	Method	Description
MergePolicy.MergeSpecification	findForcedDeletesMerges(SegmentInfos segmentInfos, MergePolicy.MergeContext mergeContext)
MergePolicy.MergeSpecification	findForcedMerges(SegmentInfos segmentInfos, int maxSegmentCount, Map<SegmentCommitInfo,Boolean> segmentsToMerge, MergePolicy.MergeContext mergeContext)
MergePolicy.MergeSpecification	findFullFlushMerges(MergeTrigger mergeTrigger, SegmentInfos segmentInfos, MergePolicy.MergeContext mergeContext)
MergePolicy.MergeSpecification	findMerges(CodecReader... readers)
MergePolicy.MergeSpecification	findMerges(MergeTrigger mergeTrigger, SegmentInfos segmentInfos, MergePolicy.MergeContext mergeContext)
void	setMinNaturalMergeNumDocs(int minNaturalMergeNumDocs)	Set the minimum number of docs that a merge must have for the resulting segment to be reordered.
void	setMinNaturalMergeRatioFromBiggestSegment(float minNaturalMergeRatioFromBiggestSegment)	Set the minimum number of docs that a merge must have for the resulting segment to be reordered, as a ratio of the total number of documents of the current biggest segment in the index.

Methods inherited from class org.apache.lucene.index.FilterMergePolicy

getMaxCFSSegmentSizeMB, getNoCFSRatio, keepFullyDeletedSegment, maxFullFlushMergeSize, numDeletesToMerge, setMaxCFSSegmentSizeMB, setNoCFSRatio, size, toString, unwrap, useCompoundFile

Methods inherited from class org.apache.lucene.index.MergePolicy

assertDelCount, isMerged, message, segString, verbose

Methods inherited from class java.lang.Object

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

Constructor Details

BPReorderingMergePolicy

public BPReorderingMergePolicy(MergePolicy in,
 BPIndexReorderer reorderer)

Sole constructor. It takes the merge policy that should be used to compute merges, and will then reorder doc IDs from all merges above the configured minimum doc count, as well as all forced merges.

If you wish to only run reordering upon forced merges, pass Integer.MAX_VALUE as a minNaturalMergeNumDocs. Otherwise a default value of 2^18 = 262,144 is suggested. This should help retain merging optimizations on small merges while reordering the larger segments that are important for good search performance.

Parameters:

in - the merge policy to use to compute merges

reorderer - the BPIndexReorderer to use to renumber doc IDs

Method Details

setMinNaturalMergeNumDocs

public void setMinNaturalMergeNumDocs(int minNaturalMergeNumDocs)

Set the minimum number of docs that a merge must have for the resulting segment to be reordered.

setMinNaturalMergeRatioFromBiggestSegment

public void setMinNaturalMergeRatioFromBiggestSegment(float minNaturalMergeRatioFromBiggestSegment)

Set the minimum number of docs that a merge must have for the resulting segment to be reordered, as a ratio of the total number of documents of the current biggest segment in the index. This parameter helps only enable reordering on segments that are large enough that they will significantly contribute to overall search performance.

findMerges

public MergePolicy.MergeSpecification findMerges(MergeTrigger mergeTrigger,
 SegmentInfos segmentInfos,
 MergePolicy.MergeContext mergeContext)
                                          throws IOException

Overrides:

findMerges in class FilterMergePolicy

Throws:

IOException

findForcedMerges

public MergePolicy.MergeSpecification findForcedMerges(SegmentInfos segmentInfos,
 int maxSegmentCount,
 Map<SegmentCommitInfo,Boolean> segmentsToMerge,
 MergePolicy.MergeContext mergeContext)
                                                throws IOException

Overrides:

findForcedMerges in class FilterMergePolicy

Throws:

IOException

findForcedDeletesMerges

public MergePolicy.MergeSpecification findForcedDeletesMerges(SegmentInfos segmentInfos,
 MergePolicy.MergeContext mergeContext)
                                                       throws IOException

Overrides:

findForcedDeletesMerges in class FilterMergePolicy

Throws:

IOException

findFullFlushMerges

public MergePolicy.MergeSpecification findFullFlushMerges(MergeTrigger mergeTrigger,
 SegmentInfos segmentInfos,
 MergePolicy.MergeContext mergeContext)
                                                   throws IOException

Overrides:

findFullFlushMerges in class FilterMergePolicy

Throws:

IOException

findMerges

public MergePolicy.MergeSpecification findMerges(CodecReader... readers)
                                          throws IOException

Overrides:

findMerges in class FilterMergePolicy

Throws:

IOException