org.apache.lucene.index

Class NoMergePolicy

java.lang.Object

org.apache.lucene.index.MergePolicy

org.apache.lucene.index.NoMergePolicy

public final class NoMergePolicy
extends MergePolicy

A MergePolicy which never returns merges to execute. Use it if you want to prevent segment merges.

Nested Class Summary

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

MergePolicy.MergeAbortedException, MergePolicy.MergeException, MergePolicy.MergeSpecification, MergePolicy.OneMerge

Field Summary

Fields

Modifier and Type	Field and Description
static MergePolicy	INSTANCE Singleton instance.

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

DEFAULT_MAX_CFS_SEGMENT_SIZE, DEFAULT_NO_CFS_RATIO, maxCFSSegmentSize, noCFSRatio

Method Summary

Modifier and Type	Method and Description
MergePolicy.MergeSpecification	findForcedDeletesMerges(SegmentInfos segmentInfos, IndexWriter writer) 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<SegmentCommitInfo,Boolean> segmentsToMerge, IndexWriter writer) Determine what set of merge operations is necessary in order to merge to <= the specified segment count.
MergePolicy.MergeSpecification	findMerges(MergeTrigger mergeTrigger, SegmentInfos segmentInfos, IndexWriter writer) Determine what set of merge operations are now necessary on the index.
double	getNoCFSRatio() Returns current noCFSRatio.
void	setMaxCFSSegmentSizeMB(double v) If a merged segment will be more than this value, leave the segment as non-compound file even if compound file is enabled.
void	setNoCFSRatio(double noCFSRatio) If a merged segment will be more than this percentage of the total size of the index, leave the segment as non-compound file even if compound file is enabled.
protected long	size(SegmentCommitInfo info, IndexWriter writer) Return the byte size of the provided SegmentCommitInfo, pro-rated by percentage of non-deleted documents is set.
String	toString()
boolean	useCompoundFile(SegmentInfos segments, SegmentCommitInfo newSegment, IndexWriter writer) 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

getMaxCFSSegmentSizeMB, isMerged

Methods inherited from class java.lang.Object

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

Field Detail

INSTANCE

public static final MergePolicy INSTANCE

Singleton instance.

Method Detail

findMerges

public MergePolicy.MergeSpecification findMerges(MergeTrigger mergeTrigger,
                                                 SegmentInfos segmentInfos,
                                                 IndexWriter writer)

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 the IndexWriter instance so only one thread at a time will call this method.

Specified by:

findMerges in class MergePolicy

Parameters:

mergeTrigger - the event that triggered the merge

segmentInfos - the total set of segments in the index

writer - the IndexWriter to find the merges on

findForcedMerges

public MergePolicy.MergeSpecification findForcedMerges(SegmentInfos segmentInfos,
                                                       int maxSegmentCount,
                                                       Map<SegmentCommitInfo,Boolean> segmentsToMerge,
                                                       IndexWriter writer)

Description 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 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.

Specified by:

findForcedMerges in class MergePolicy

Parameters:

segmentInfos - the total set of segments in the index

maxSegmentCount - 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.

writer - the IndexWriter to find the merges on

findForcedDeletesMerges

public MergePolicy.MergeSpecification findForcedDeletesMerges(SegmentInfos segmentInfos,
                                                              IndexWriter writer)

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 class MergePolicy

Parameters:

segmentInfos - the total set of segments in the index

writer - the IndexWriter to find the merges on

useCompoundFile

public boolean useCompoundFile(SegmentInfos segments,
                               SegmentCommitInfo newSegment,
                               IndexWriter writer)

Description copied from class: MergePolicy

Returns true if a new segment (regardless of its origin) should use the compound file format. The default implementation returns true iff the size of the given mergedInfo is less or equal to MergePolicy.getMaxCFSSegmentSizeMB() and the size is less or equal to the TotalIndexSize * MergePolicy.getNoCFSRatio() otherwise false.

Overrides:

useCompoundFile in class MergePolicy

size

protected long size(SegmentCommitInfo info,
                    IndexWriter writer)
             throws IOException

Description copied from class: MergePolicy

Return the byte size of the provided SegmentCommitInfo, pro-rated by percentage of non-deleted documents is set.

Overrides:

size in class MergePolicy

Throws:

IOException

getNoCFSRatio

public double getNoCFSRatio()

Description copied from class: MergePolicy

Returns current noCFSRatio.

Overrides:

getNoCFSRatio in class MergePolicy

See Also:

MergePolicy.setNoCFSRatio(double)

setMaxCFSSegmentSizeMB

public void setMaxCFSSegmentSizeMB(double v)

Description copied from class: MergePolicy

If a merged segment will be more than this value, leave the segment as non-compound file even if compound file is enabled. Set this to Double.POSITIVE_INFINITY (default) and noCFSRatio to 1.0 to always use CFS regardless of merge size.

Overrides:

setMaxCFSSegmentSizeMB in class MergePolicy

setNoCFSRatio

public void setNoCFSRatio(double noCFSRatio)

Description copied from class: MergePolicy

If a merged segment will be more than this percentage of the total size of the index, leave the segment as non-compound file even if compound file is enabled. Set to 1.0 to always use CFS regardless of merge size.

Overrides:

setNoCFSRatio in class MergePolicy

toString

public String toString()

Overrides:

toString in class Object