Class MergePolicy

    • Field Detail

      • DEFAULT_NO_CFS_RATIO

        protected static final double DEFAULT_NO_CFS_RATIO
        Default ratio for compound file system usage. Set to 1.0, always use compound file system.
        See Also:
        Constant Field Values
      • DEFAULT_MAX_CFS_SEGMENT_SIZE

        protected static final long DEFAULT_MAX_CFS_SEGMENT_SIZE
        Default max segment size in order to use compound file system. Set to Long.MAX_VALUE.
        See Also:
        Constant Field Values
      • noCFSRatio

        protected double noCFSRatio
        If the size of the merge segment exceeds this ratio of the total index size then it will remain in non-compound format
      • maxCFSSegmentSize

        protected long maxCFSSegmentSize
        If the size of the merged segment exceeds this value then it will not use compound file format.
    • Constructor Detail

      • MergePolicy

        protected MergePolicy​(double defaultNoCFSRatio,
                              long defaultMaxCFSSegmentSize)
        Creates a new merge policy instance with default settings for noCFSRatio and maxCFSSegmentSize. This ctor should be used by subclasses using different defaults than the MergePolicy
    • Method Detail

      • setIndexWriter

        public void setIndexWriter​(IndexWriter writer)
        Sets the 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.
        See Also:
        SetOnce
      • findForcedMerges

        public abstract MergePolicy.MergeSpecification findForcedMerges​(SegmentInfos segmentInfos,
                                                                        int maxSegmentCount,
                                                                        Map<SegmentCommitInfo,​Boolean> segmentsToMerge)
                                                                 throws IOException
        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.
        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.
        Throws:
        IOException
      • findForcedDeletesMerges

        public abstract MergePolicy.MergeSpecification findForcedDeletesMerges​(SegmentInfos segmentInfos)
                                                                        throws IOException
        Determine what set of merge operations is necessary in order to expunge all deletes from the index.
        Parameters:
        segmentInfos - the total set of segments in the index
        Throws:
        IOException
      • close

        public abstract void close()
        Release all resources for the policy.
        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable
      • isMerged

        protected final boolean isMerged​(SegmentInfos infos,
                                         SegmentCommitInfo info)
                                  throws IOException
        Returns true if this single info is already fully merged (has no pending deletes, is in the same dir as the writer, and matches the current compound file setting
        Throws:
        IOException
      • getNoCFSRatio

        public final double getNoCFSRatio()
        Returns current noCFSRatio.
        See Also:
        setNoCFSRatio(double)
      • setNoCFSRatio

        public final 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. Set to 1.0 to always use CFS regardless of merge size.
      • getMaxCFSSegmentSizeMB

        public final double getMaxCFSSegmentSizeMB()
        Returns the largest size allowed for a compound file segment
      • setMaxCFSSegmentSizeMB

        public final 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. Set this to Double.POSITIVE_INFINITY (default) and noCFSRatio to 1.0 to always use CFS regardless of merge size.