Package org.apache.lucene.index
Class UpgradeIndexMergePolicy
java.lang.Object
org.apache.lucene.index.MergePolicy
org.apache.lucene.index.UpgradeIndexMergePolicy
- All Implemented Interfaces:
Closeable
,AutoCloseable
,Cloneable
This
MergePolicy
is used for upgrading all existing segments of
an index when calling IndexWriter.forceMerge(int)
.
All other methods delegate to the base MergePolicy
given 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 other MergePolicy
and call IndexWriter.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 MergePolicy
may also reorder documents.
- See Also:
-
Nested Class Summary
Nested classes/interfaces inherited from class org.apache.lucene.index.MergePolicy
MergePolicy.DocMap, MergePolicy.MergeAbortedException, MergePolicy.MergeException, MergePolicy.MergeSpecification, MergePolicy.MergeTrigger, MergePolicy.OneMerge
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Field Summary
FieldsFields inherited from class org.apache.lucene.index.MergePolicy
DEFAULT_MAX_CFS_SEGMENT_SIZE, DEFAULT_NO_CFS_RATIO, maxCFSSegmentSize, noCFSRatio, writer
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Constructor Summary
ConstructorsConstructorDescriptionWrap the givenMergePolicy
and intercept forceMerge requests to only upgrade segments written with previous Lucene versions. -
Method Summary
Modifier and TypeMethodDescriptionvoid
close()
Release all resources for the policy.findForcedDeletesMerges
(SegmentInfos segmentInfos) Determine what set of merge operations is necessary in order to expunge all deletes from the index.findForcedMerges
(SegmentInfos segmentInfos, int maxSegmentCount, Map<SegmentCommitInfo, Boolean> segmentsToMerge) Determine what set of merge operations is necessary in order to merge to <= the specified segment count.findMerges
(MergePolicy.MergeTrigger mergeTrigger, SegmentInfos segmentInfos) Determine what set of merge operations are now necessary on the index.void
setIndexWriter
(IndexWriter writer) Sets theIndexWriter
to use by this merge policy.protected boolean
Returns if the given segment should be upgraded.toString()
boolean
useCompoundFile
(SegmentInfos segments, SegmentCommitInfo newSegment) Returns true if a new segment (regardless of its origin) should use the compound file format.Methods inherited from class org.apache.lucene.index.MergePolicy
clone, getMaxCFSSegmentSizeMB, getNoCFSRatio, isMerged, setMaxCFSSegmentSizeMB, setNoCFSRatio, size
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Field Details
-
base
WrappedMergePolicy
.
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Constructor Details
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UpgradeIndexMergePolicy
Wrap the givenMergePolicy
and intercept forceMerge requests to only upgrade segments written with previous Lucene versions.
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Method Details
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shouldUpgradeSegment
Returns if the given segment should be upgraded. The default implementation will return!Constants.LUCENE_MAIN_VERSION.equals(si.getVersion())
, so all segments created with a different version number than this Lucene version will get upgraded. -
setIndexWriter
Description copied from class:MergePolicy
Sets theIndexWriter
to use by this merge policy. This method is allowed to be called only once, and is usually set by IndexWriter. If it is called more than once,SetOnce.AlreadySetException
is thrown.- Overrides:
setIndexWriter
in classMergePolicy
- See Also:
-
findMerges
public MergePolicy.MergeSpecification findMerges(MergePolicy.MergeTrigger mergeTrigger, SegmentInfos segmentInfos) throws IOException Description copied from class:MergePolicy
Determine what set of merge operations are now necessary on the index.IndexWriter
calls this whenever there is a change to the segments. This call is always synchronized on theIndexWriter
instance so only one thread at a time will call this method.- Specified by:
findMerges
in classMergePolicy
- Parameters:
mergeTrigger
- the event that triggered the mergesegmentInfos
- the total set of segments in the index- Throws:
IOException
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findForcedMerges
public MergePolicy.MergeSpecification findForcedMerges(SegmentInfos segmentInfos, int maxSegmentCount, Map<SegmentCommitInfo, Boolean> segmentsToMerge) throws IOExceptionDescription copied from class:MergePolicy
Determine what set of merge operations is necessary in order to merge to <= the specified segment count.IndexWriter
calls this when itsIndexWriter.forceMerge(int)
method is called. This call is always synchronized on theIndexWriter
instance so only one thread at a time will call this method.- Specified by:
findForcedMerges
in classMergePolicy
- Parameters:
segmentInfos
- the total set of segments in the indexmaxSegmentCount
- requested maximum number of segments in the index (currently this is always 1)segmentsToMerge
- 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.- Throws:
IOException
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findForcedDeletesMerges
public MergePolicy.MergeSpecification findForcedDeletesMerges(SegmentInfos segmentInfos) throws IOException Description copied from class:MergePolicy
Determine what set of merge operations is necessary in order to expunge all deletes from the index.- Specified by:
findForcedDeletesMerges
in classMergePolicy
- Parameters:
segmentInfos
- the total set of segments in the index- Throws:
IOException
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useCompoundFile
public boolean useCompoundFile(SegmentInfos segments, SegmentCommitInfo newSegment) throws IOException Description copied from class:MergePolicy
Returns true if a new segment (regardless of its origin) should use the compound file format. The default implementation returnstrue
iff the size of the given mergedInfo is less or equal toMergePolicy.getMaxCFSSegmentSizeMB()
and the size is less or equal to the TotalIndexSize *MergePolicy.getNoCFSRatio()
otherwisefalse
.- Overrides:
useCompoundFile
in classMergePolicy
- Throws:
IOException
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close
public void close()Description copied from class:MergePolicy
Release all resources for the policy.- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceCloseable
- Specified by:
close
in classMergePolicy
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toString
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