org.apache.lucene.index

Class SortingMergePolicy

java.lang.Object

org.apache.lucene.index.MergePolicy

org.apache.lucene.index.SortingMergePolicy

public final class SortingMergePolicy
extends MergePolicy

A MergePolicy that reorders documents according to a Sort before merging them. As a consequence, all segments resulting from a merge will be sorted while segments resulting from a flush will be in the order in which documents have been added.

NOTE: Never use this policy if you rely on IndexWriter.addDocuments to have sequentially-assigned doc IDs, this policy will scatter doc IDs.

NOTE: This policy should only be used with idempotent Sorts so that the order of segments is predictable. For example, using Sort.INDEXORDER in reverse (which is not idempotent) will make the order of documents in a segment depend on the number of times the segment has been merged.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Nested Class Summary

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

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

Field Summary

Fields

Modifier and Type	Field and Description
static String	SORTER_ID_PROP Put in the diagnostics to denote that this segment is sorted.

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

DEFAULT_MAX_CFS_SEGMENT_SIZE, DEFAULT_NO_CFS_RATIO, maxCFSSegmentSize, noCFSRatio

Constructor Summary

Constructors

Constructor and Description
SortingMergePolicy(MergePolicy in, Sort sort) Create a new MergePolicy that sorts documents with the given sort.

Method Summary

Methods

Modifier and Type	Method and Description
MergePolicy.MergeSpecification	findForcedDeletesMerges(SegmentInfos segmentInfos, IndexWriter writer)
MergePolicy.MergeSpecification	findForcedMerges(SegmentInfos segmentInfos, int maxSegmentCount, Map<SegmentCommitInfo,Boolean> segmentsToMerge, IndexWriter writer)
MergePolicy.MergeSpecification	findMerges(MergeTrigger mergeTrigger, SegmentInfos segmentInfos, IndexWriter writer)
Sort	getSort() Return the Sort order that is used to sort segments when merging.
boolean	isSorted(LeafReader reader) Returns true if the given reader is sorted by the sort order of this SortingMergePolicy.
String	toString()
boolean	useCompoundFile(SegmentInfos segments, SegmentCommitInfo newSegment, IndexWriter writer)

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

getMaxCFSSegmentSizeMB, getNoCFSRatio, isMerged, setMaxCFSSegmentSizeMB, setNoCFSRatio, size

Methods inherited from class java.lang.Object

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

Field Detail

SORTER_ID_PROP

public static final String SORTER_ID_PROP

Put in the diagnostics to denote that this segment is sorted.

See Also:

Constant Field Values

Constructor Detail

SortingMergePolicy

public SortingMergePolicy(MergePolicy in,
                  Sort sort)

Create a new MergePolicy that sorts documents with the given sort.

Method Detail

isSorted

public boolean isSorted(LeafReader reader)

Returns true if the given reader is sorted by the sort order of this SortingMergePolicy.

getSort

public Sort getSort()

Return the Sort order that is used to sort segments when merging.

findMerges

public MergePolicy.MergeSpecification findMerges(MergeTrigger mergeTrigger,
                                        SegmentInfos segmentInfos,
                                        IndexWriter writer)
                                          throws IOException

Specified by:

findMerges in class MergePolicy

Throws:

IOException

findForcedMerges

public MergePolicy.MergeSpecification findForcedMerges(SegmentInfos segmentInfos,
                                              int maxSegmentCount,
                                              Map<SegmentCommitInfo,Boolean> segmentsToMerge,
                                              IndexWriter writer)
                                                throws IOException

Specified by:

findForcedMerges in class MergePolicy

Throws:

IOException

findForcedDeletesMerges

public MergePolicy.MergeSpecification findForcedDeletesMerges(SegmentInfos segmentInfos,
                                                     IndexWriter writer)
                                                       throws IOException

Specified by:

findForcedDeletesMerges in class MergePolicy

Throws:

IOException

useCompoundFile

public boolean useCompoundFile(SegmentInfos segments,
                      SegmentCommitInfo newSegment,
                      IndexWriter writer)
                        throws IOException

Overrides:

useCompoundFile in class MergePolicy

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object