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.

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

Modifier and Type	Method and Description
MergePolicy.MergeSpecification	findForcedDeletesMerges(SegmentInfos segmentInfos, IndexWriter writer) Determine what set of merge operations is necessary in order to expunge all deletes from the index.
MergePolicy.MergeSpecification	findForcedMerges(SegmentInfos segmentInfos, int maxSegmentCount, Map<SegmentCommitInfo,Boolean> segmentsToMerge, IndexWriter writer) Determine what set of merge operations is necessary in order to merge to <= the specified segment count.
MergePolicy.MergeSpecification	findMerges(MergeTrigger mergeTrigger, SegmentInfos segmentInfos, IndexWriter writer) Determine what set of merge operations are now necessary on the index.
Sort	getSort() Return the Sort order that is used to sort segments when merging.
static boolean	isSorted(LeafReader reader, Sort sort) Returns true if the given reader is sorted by the sort given.
protected long	size(SegmentCommitInfo info, IndexWriter writer) Return the byte size of the provided SegmentCommitInfo, pro-rated by percentage of non-deleted documents is set.
String	toString()
boolean	useCompoundFile(SegmentInfos segments, SegmentCommitInfo newSegment, IndexWriter writer) Returns true if a new segment (regardless of its origin) should use the compound file format.

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

getMaxCFSSegmentSizeMB, getNoCFSRatio, isMerged, setMaxCFSSegmentSizeMB, setNoCFSRatio

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 static boolean isSorted(LeafReader reader,
                               Sort sort)

Returns true if the given reader is sorted by the sort given. Typically the given sort would be the getSort() order of a 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

Description copied from class: MergePolicy

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.

Specified by:

findMerges in class MergePolicy

Parameters:

mergeTrigger - the event that triggered the merge

segmentInfos - the total set of segments in the index

writer - the IndexWriter to find the merges on

Throws:

IOException

findForcedMerges

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

Description copied from class: MergePolicy

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.

Specified by:

findForcedMerges in class MergePolicy

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.

writer - the IndexWriter to find the merges on

Throws:

IOException

findForcedDeletesMerges

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

Description copied from class: MergePolicy

Determine what set of merge operations is necessary in order to expunge all deletes from the index.

Specified by:

findForcedDeletesMerges in class MergePolicy

Parameters:

segmentInfos - the total set of segments in the index

writer - the IndexWriter to find the merges on

Throws:

IOException

useCompoundFile

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

Description copied from class: MergePolicy

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 MergePolicy.getMaxCFSSegmentSizeMB() and the size is less or equal to the TotalIndexSize * MergePolicy.getNoCFSRatio() otherwise false.

Overrides:

useCompoundFile in class MergePolicy

Throws:

IOException

size

protected long size(SegmentCommitInfo info,
                    IndexWriter writer)
             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

toString

public String toString()

Overrides:

toString in class Object