Package org.apache.lucene.index

Class LogByteSizeMergePolicy

java.lang.Object
org.apache.lucene.index.MergePolicy
org.apache.lucene.index.LogMergePolicy
org.apache.lucene.index.LogByteSizeMergePolicy
public class LogByteSizeMergePolicy extends LogMergePolicy
This is a LogMergePolicy that measures size of a segment as the total byte size of the segment's files.

  • Field Details

    • DEFAULT_MIN_MERGE_MB

      public static final double DEFAULT_MIN_MERGE_MB
      Default minimum segment size. @see setMinMergeMB
      See Also:

    • DEFAULT_MAX_MERGE_MB

      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
      See Also:

    • DEFAULT_MAX_MERGE_MB_FOR_FORCED_MERGE

      public static final double DEFAULT_MAX_MERGE_MB_FOR_FORCED_MERGE
      Default maximum segment size. A segment of this size or larger will never be merged during forceMerge. @see setMaxMergeMBForForceMerge
      See Also:

  • Constructor Details

    • LogByteSizeMergePolicy

      public LogByteSizeMergePolicy()
      Sole constructor, setting all settings to their defaults.

  • Method Details

    • size

      protected long size(SegmentCommitInfo info, MergePolicy.MergeContext mergeContext) 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

    • setMaxMergeMB

      public void setMaxMergeMB(double mb)
      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 LogMergePolicy.setMaxMergeDocs(int) is also used to check whether a segment is too large for merging (it's either or).

    • getMaxMergeMB

      public double getMaxMergeMB()
      Returns the largest segment (measured by total byte size of the segment's files, in MB) that may be merged with other segments.
      See Also:

    • setMaxMergeMBForForcedMerge

      public void setMaxMergeMBForForcedMerge(double mb)
      Determines the largest segment (measured by total byte size of the segment's files, in MB) that may be merged with other segments during forceMerge. Setting it low will leave the index with more than 1 segment, even if IndexWriter.forceMerge(int) is called.

    • getMaxMergeMBForForcedMerge

      public double getMaxMergeMBForForcedMerge()
      Returns the largest segment (measured by total byte size of the segment's files, in MB) that may be merged with other segments during forceMerge.
      See Also:

    • setMinMergeMB

      public void setMinMergeMB(double mb)
      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).

    • getMinMergeMB

      public double getMinMergeMB()
      Get the minimum size for a segment to remain un-merged.
      See Also: