org.apache.lucene.index
Class LogDocMergePolicy

java.lang.Object
  org.apache.lucene.index.MergePolicy
      org.apache.lucene.index.LogMergePolicy
          org.apache.lucene.index.LogDocMergePolicy

All Implemented Interfaces:

Closeable

public class LogDocMergePolicy
extends LogMergePolicy

This is a LogMergePolicy that measures size of a segment as the number of documents (not taking deletions into account).

Nested Class Summary

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

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

Field Summary

static int

DEFAULT_MIN_MERGE_DOCS Default minimum segment size.

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

calibrateSizeByDeletes, DEFAULT_MAX_MERGE_DOCS, DEFAULT_MERGE_FACTOR, DEFAULT_NO_CFS_RATIO, LEVEL_LOG_SPAN, maxMergeDocs, maxMergeSize, maxMergeSizeForForcedMerge, mergeFactor, minMergeSize, noCFSRatio, useCompoundFile

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

writer

Constructor Summary

LogDocMergePolicy()

Method Summary

int	getMinMergeDocs() Get the minimum size for a segment to remain un-merged.
void	setMinMergeDocs(int minMergeDocs) Sets the minimum size for the lowest level segments.
protected long	size(SegmentInfo info)

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

close, findForcedDeletesMerges, findForcedMerges, findMerges, getCalibrateSizeByDeletes, getMaxMergeDocs, getMergeFactor, getNoCFSRatio, getUseCompoundFile, isMerged, isMerged, message, setCalibrateSizeByDeletes, setMaxMergeDocs, setMergeFactor, setNoCFSRatio, setUseCompoundFile, sizeBytes, sizeDocs, toString, useCompoundFile, verbose

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

setIndexWriter

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_MIN_MERGE_DOCS

public static final int DEFAULT_MIN_MERGE_DOCS

Default minimum segment size. @see setMinMergeDocs

See Also:

Constant Field Values

Constructor Detail

LogDocMergePolicy

public LogDocMergePolicy()

Method Detail

size

protected long size(SegmentInfo info)
             throws IOException

Specified by:

size in class LogMergePolicy

Throws:

IOException

setMinMergeDocs

public void setMinMergeDocs(int minMergeDocs)

Sets the minimum size for the lowest level segments. Any segments below this size are considered to be on the same level (even if they vary drastically in size) and will be merged whenever there are mergeFactor of them. This effectively truncates the "long tail" of small segments that would otherwise be created into a single level. If you set this too large, it could greatly increase the merging cost during indexing (if you flush many small segments).

getMinMergeDocs

public int getMinMergeDocs()

Get the minimum size for a segment to remain un-merged.

See Also:

setMinMergeDocs(int)