public class UpgradeIndexMergePolicy extends MergePolicy
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.
IndexUpgrader
MergePolicy.MergeAbortedException, MergePolicy.MergeException, MergePolicy.MergeSpecification, MergePolicy.MergeTrigger, MergePolicy.OneMerge
Modifier and Type | Field and Description |
---|---|
protected MergePolicy |
base
Wrapped
MergePolicy . |
writer
Constructor and Description |
---|
UpgradeIndexMergePolicy(MergePolicy base)
Wrap the given
MergePolicy and intercept forceMerge requests to
only upgrade segments written with previous Lucene versions. |
Modifier and Type | Method and Description |
---|---|
void |
close()
Release all resources for the policy.
|
MergePolicy.MergeSpecification |
findForcedDeletesMerges(SegmentInfos segmentInfos)
Determine what set of merge operations is necessary in order to expunge all
deletes from the index.
|
MergePolicy.MergeSpecification |
findForcedMerges(SegmentInfos segmentInfos,
int maxSegmentCount,
Map<SegmentInfoPerCommit,Boolean> segmentsToMerge)
Determine what set of merge operations is necessary in
order to merge to <= the specified segment count.
|
MergePolicy.MergeSpecification |
findMerges(MergePolicy.MergeTrigger mergeTrigger,
SegmentInfos segmentInfos)
Determine what set of merge operations are now necessary on the index.
|
void |
setIndexWriter(IndexWriter writer)
Sets the
IndexWriter to use by this merge policy. |
protected boolean |
shouldUpgradeSegment(SegmentInfoPerCommit si)
Returns if the given segment should be upgraded.
|
String |
toString() |
boolean |
useCompoundFile(SegmentInfos segments,
SegmentInfoPerCommit newSegment)
Returns true if a new segment (regardless of its origin) should use the compound file format.
|
clone
protected final MergePolicy base
MergePolicy
.public UpgradeIndexMergePolicy(MergePolicy base)
MergePolicy
and intercept forceMerge requests to
only upgrade segments written with previous Lucene versions.protected boolean shouldUpgradeSegment(SegmentInfoPerCommit si)
!Constants.LUCENE_MAIN_VERSION.equals(si.getVersion())
,
so all segments created with a different version number than this Lucene version will
get upgraded.public void setIndexWriter(IndexWriter writer)
MergePolicy
IndexWriter
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.setIndexWriter
in class MergePolicy
SetOnce
public MergePolicy.MergeSpecification findMerges(MergePolicy.MergeTrigger mergeTrigger, SegmentInfos segmentInfos) throws IOException
MergePolicy
IndexWriter
calls this whenever there is a change to the segments.
This call is always synchronized on the IndexWriter
instance so
only one thread at a time will call this method.findMerges
in class MergePolicy
mergeTrigger
- the event that triggered the mergesegmentInfos
- the total set of segments in the indexIOException
public MergePolicy.MergeSpecification findForcedMerges(SegmentInfos segmentInfos, int maxSegmentCount, Map<SegmentInfoPerCommit,Boolean> segmentsToMerge) throws IOException
MergePolicy
IndexWriter
calls this when its
IndexWriter.forceMerge(int)
method is called. This call is always
synchronized on the IndexWriter
instance so only one thread at a
time will call this method.findForcedMerges
in class MergePolicy
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.IOException
public MergePolicy.MergeSpecification findForcedDeletesMerges(SegmentInfos segmentInfos) throws IOException
MergePolicy
findForcedDeletesMerges
in class MergePolicy
segmentInfos
- the total set of segments in the indexIOException
public boolean useCompoundFile(SegmentInfos segments, SegmentInfoPerCommit newSegment) throws IOException
MergePolicy
useCompoundFile
in class MergePolicy
IOException
public void close()
MergePolicy
close
in interface Closeable
close
in class MergePolicy
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