org.apache.lucene.index: public class: LogByteSizeMergePolicy

org.apache.lucene.index
public class: LogByteSizeMergePolicy [javadoc | source]

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

This is a LogMergePolicy that measures size of a segment as the total byte size of the segment's files.

Field Summary
public static final double	DEFAULT_MIN_MERGE_MB	Default minimum segment size. @see setMinMergeMB
public static final double	DEFAULT_MAX_MERGE_MB	Default maximum segment size. A segment of this size or larger will never be merged. @see setMaxMergeMB

Fields inherited from org.apache.lucene.index.LogMergePolicy:
LEVEL_LOG_SPAN, DEFAULT_MERGE_FACTOR, DEFAULT_MAX_MERGE_DOCS, minMergeSize, maxMergeSize, maxMergeDocs

Constructor:
public LogByteSizeMergePolicy() { super(); minMergeSize = (long) (DEFAULT_MIN_MERGE_MB10241024); maxMergeSize = (long) (DEFAULT_MAX_MERGE_MB10241024); }

Constructor:

 public LogByteSizeMergePolicy() {
    
    super();
    minMergeSize = (long) (DEFAULT_MIN_MERGE_MB*1024*1024);
    maxMergeSize = (long) (DEFAULT_MAX_MERGE_MB*1024*1024);
}

Method from org.apache.lucene.index.LogByteSizeMergePolicy Summary:
getMaxMergeMB, getMinMergeMB, setMaxMergeMB, setMinMergeMB, size

Methods from org.apache.lucene.index.LogMergePolicy:
close, findMerges, findMergesForOptimize, findMergesToExpungeDeletes, getMaxMergeDocs, getMergeFactor, getUseCompoundDocStore, getUseCompoundFile, setMaxMergeDocs, setMergeFactor, setUseCompoundDocStore, setUseCompoundFile, size, useCompoundDocStore, useCompoundFile

Methods from org.apache.lucene.index.MergePolicy:
close, findMerges, findMergesForOptimize, findMergesToExpungeDeletes, useCompoundDocStore, useCompoundFile

Methods from java.lang.Object:
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from org.apache.lucene.index.LogByteSizeMergePolicy Detail:
public double getMaxMergeMB() { return ((double) maxMergeSize)/1024/1024; } Returns the largest segment (meaured by total byte size of the segment's files, in MB) that may be merged with other segments.
public double getMinMergeMB() { return ((double) minMergeSize)/1024/1024; } Get the minimum size for a segment to remain un-merged.
public void setMaxMergeMB(double mb) { maxMergeSize = (long) (mb10241024); } Determines the largest segment (measured by total byte size of the segment's files, in MB) that may be merged with other segments. Small values (e.g., less than 50 MB) are best for interactive indexing, as this limits the length of pauses while indexing to a few seconds. Larger values are best for batched indexing and speedier searches. Note that #setMaxMergeDocs is also used to check whether a segment is too large for merging (it's either or).
public void setMinMergeMB(double mb) { minMergeSize = (long) (mb10241024); } 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).
protected long size(SegmentInfo info) throws IOException { return info.sizeInBytes(); }

Method from org.apache.lucene.index.LogByteSizeMergePolicy Detail:

 public double getMaxMergeMB() {
    return ((double) maxMergeSize)/1024/1024;
}

Returns the largest segment (meaured by total byte size of the segment's files, in MB) that may be merged with other segments.

 public double getMinMergeMB() {
    return ((double) minMergeSize)/1024/1024;
}

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

 public  void setMaxMergeMB(double mb) {
    maxMergeSize = (long) (mb*1024*1024);
}

Determines the largest segment (measured by total byte size of the segment's files, in MB) that may be merged with other segments. Small values (e.g., less than 50 MB) are best for interactive indexing, as this limits the length of pauses while indexing to a few seconds. Larger values are best for batched indexing and speedier searches.

Note that #setMaxMergeDocs is also used to check whether a segment is too large for merging (it's either or).

 public  void setMinMergeMB(double mb) {
    minMergeSize = (long) (mb*1024*1024);
}

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).

 protected long size(SegmentInfo info) throws IOException {
    return info.sizeInBytes();
}