Class MergePolicy

    • Constructor Detail

    • 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
      • findMerges

        public abstract MergePolicy.MergeSpecification findMerges​(MergePolicy.MergeTrigger mergeTrigger,
                                                                  SegmentInfos segmentInfos)
                                                           throws java.io.IOException
        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.
        Parameters:
        mergeTrigger - the event that triggered the merge
        segmentInfos - the total set of segments in the index
        Throws:
        java.io.IOException
      • findForcedMerges

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

        public abstract MergePolicy.MergeSpecification findForcedDeletesMerges​(SegmentInfos segmentInfos)
                                                                        throws java.io.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:
        java.io.IOException
      • close

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

        public boolean useCompoundFile​(SegmentInfos infos,
                                       SegmentCommitInfo mergedInfo)
                                throws java.io.IOException
        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 getMaxCFSSegmentSizeMB() and the size is less or equal to the TotalIndexSize * getNoCFSRatio() otherwise false.
        Throws:
        java.io.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.