Package org.apache.lucene.index
Class UpgradeIndexMergePolicy
- java.lang.Object
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- org.apache.lucene.index.MergePolicy
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- org.apache.lucene.index.FilterMergePolicy
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- org.apache.lucene.index.UpgradeIndexMergePolicy
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- All Implemented Interfaces:
Unwrappable<MergePolicy>
public class UpgradeIndexMergePolicy extends FilterMergePolicy
ThisMergePolicyis used for upgrading all existing segments of an index when callingIndexWriter.forceMerge(int). All other methods delegate to the baseMergePolicygiven to the constructor. This allows for an as-cheap-as possible upgrade of an older index by only upgrading segments that are created by previous Lucene versions. forceMerge does no longer really merge; it is just used to "forceMerge" older segment versions away.In general one would use
IndexUpgrader, but for a fully customizeable upgrade, you can use this like any otherMergePolicyand callIndexWriter.forceMerge(int):IndexWriterConfig iwc = new IndexWriterConfig(Version.LUCENE_XX, new KeywordAnalyzer()); iwc.setMergePolicy(new UpgradeIndexMergePolicy(iwc.getMergePolicy())); IndexWriter w = new IndexWriter(dir, iwc); w.forceMerge(1); w.close();
Warning: This merge policy may reorder documents if the index was partially upgraded before calling forceMerge (e.g., documents were added). If your application relies on "monotonicity" of doc IDs (which means that the order in which the documents were added to the index is preserved), do a forceMerge(1) instead. Please note, the delegate
MergePolicymay also reorder documents.- See Also:
IndexUpgrader- WARNING: This API is experimental and might change in incompatible ways in the next release.
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.lucene.index.MergePolicy
MergePolicy.MergeAbortedException, MergePolicy.MergeContext, MergePolicy.MergeException, MergePolicy.MergeSpecification, MergePolicy.OneMerge, MergePolicy.OneMergeProgress
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Field Summary
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Fields inherited from class org.apache.lucene.index.FilterMergePolicy
in
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Fields inherited from class org.apache.lucene.index.MergePolicy
DEFAULT_MAX_CFS_SEGMENT_SIZE, DEFAULT_NO_CFS_RATIO, maxCFSSegmentSize, noCFSRatio
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Constructor Summary
Constructors Constructor Description UpgradeIndexMergePolicy(MergePolicy in)Wrap the givenMergePolicyand intercept forceMerge requests to only upgrade segments written with previous Lucene versions.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description MergePolicy.MergeSpecificationfindForcedMerges(SegmentInfos segmentInfos, int maxSegmentCount, Map<SegmentCommitInfo,Boolean> segmentsToMerge, MergePolicy.MergeContext mergeContext)Determine what set of merge operations is necessary in order to merge to<=the specified segment count.MergePolicy.MergeSpecificationfindMerges(MergeTrigger mergeTrigger, SegmentInfos segmentInfos, MergePolicy.MergeContext mergeContext)Determine what set of merge operations are now necessary on the index.protected booleanshouldUpgradeSegment(SegmentCommitInfo si)Returns if the given segment should be upgraded.-
Methods inherited from class org.apache.lucene.index.FilterMergePolicy
findForcedDeletesMerges, findFullFlushMerges, findMerges, getMaxCFSSegmentSizeMB, getNoCFSRatio, keepFullyDeletedSegment, maxFullFlushMergeSize, numDeletesToMerge, setMaxCFSSegmentSizeMB, setNoCFSRatio, size, toString, unwrap, useCompoundFile
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Methods inherited from class org.apache.lucene.index.MergePolicy
assertDelCount, isMerged, message, segString, verbose
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Constructor Detail
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UpgradeIndexMergePolicy
public UpgradeIndexMergePolicy(MergePolicy in)
Wrap the givenMergePolicyand intercept forceMerge requests to only upgrade segments written with previous Lucene versions.
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Method Detail
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shouldUpgradeSegment
protected boolean shouldUpgradeSegment(SegmentCommitInfo si)
Returns if the given segment should be upgraded. The default implementation will return!Version.LATEST.equals(si.getVersion()), so all segments created with a different version number than this Lucene version will get upgraded.
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findMerges
public MergePolicy.MergeSpecification findMerges(MergeTrigger mergeTrigger, SegmentInfos segmentInfos, MergePolicy.MergeContext mergeContext) throws IOException
Description copied from class:MergePolicyDetermine what set of merge operations are now necessary on the index.IndexWritercalls this whenever there is a change to the segments. This call is always synchronized on theIndexWriterinstance so only one thread at a time will call this method.- Overrides:
findMergesin classFilterMergePolicy- Parameters:
mergeTrigger- the event that triggered the mergesegmentInfos- the total set of segments in the indexmergeContext- the IndexWriter to find the merges on- Throws:
IOException
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findForcedMerges
public MergePolicy.MergeSpecification findForcedMerges(SegmentInfos segmentInfos, int maxSegmentCount, Map<SegmentCommitInfo,Boolean> segmentsToMerge, MergePolicy.MergeContext mergeContext) throws IOException
Description copied from class:MergePolicyDetermine what set of merge operations is necessary in order to merge to<=the specified segment count.IndexWritercalls this when itsIndexWriter.forceMerge(int)method is called. This call is always synchronized on theIndexWriterinstance so only one thread at a time will call this method.- Overrides:
findForcedMergesin classFilterMergePolicy- Parameters:
segmentInfos- the total set of segments in the indexmaxSegmentCount- requested maximum number of segments in the indexsegmentsToMerge- contains the specific SegmentInfo instances that must be merged away. This may be a subset of all SegmentInfos. If the value is True for a given SegmentInfo, that means this segment was an original segment present in the to-be-merged index; else, it was a segment produced by a cascaded merge.mergeContext- the MergeContext to find the merges on- Throws:
IOException
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