Package org.apache.lucene.index

Class SoftDeletesRetentionMergePolicy

java.lang.Object

org.apache.lucene.index.MergePolicy

org.apache.lucene.index.FilterMergePolicy

org.apache.lucene.index.OneMergeWrappingMergePolicy

org.apache.lucene.index.SoftDeletesRetentionMergePolicy

All Implemented Interfaces:

Unwrappable<MergePolicy>

public final class SoftDeletesRetentionMergePolicy
extends OneMergeWrappingMergePolicy

This MergePolicy allows to carry over soft deleted documents across merges. The policy wraps the merge reader and marks documents as "live" that have a value in the soft delete field and match the provided query. This allows for instance to keep documents alive based on time or any other constraint in the index. The main purpose for this merge policy is to implement retention policies for document modification to vanish in the index. Using this merge policy allows to control when soft deletes are claimed by merges.

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.MergeAbortedException, MergePolicy.MergeContext, MergePolicy.MergeException, MergePolicy.MergeSpecification, MergePolicy.OneMerge, MergePolicy.OneMergeProgress

Field Summary

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

in

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

DEFAULT_MAX_CFS_SEGMENT_SIZE, DEFAULT_NO_CFS_RATIO, maxCFSSegmentSize, noCFSRatio

Constructor Summary

Constructors

Constructor	Description
SoftDeletesRetentionMergePolicy(String field, Supplier<Query> retentionQuerySupplier, MergePolicy in)	Creates a new SoftDeletesRetentionMergePolicy

Method Summary

Modifier and Type	Method	Description
boolean	keepFullyDeletedSegment(IOSupplier<CodecReader> readerIOSupplier)	Returns true if the segment represented by the given CodecReader should be keep even if it's fully deleted.
int	numDeletesToMerge(SegmentCommitInfo info, int delCount, IOSupplier<CodecReader> readerSupplier)	Returns the number of deletes that a merge would claim on the given segment.

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

findForcedDeletesMerges, findForcedMerges, findFullFlushMerges, findMerges

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

getMaxCFSSegmentSizeMB, getNoCFSRatio, setMaxCFSSegmentSizeMB, setNoCFSRatio, size, toString, unwrap, useCompoundFile

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

assertDelCount, isMerged, message, segString, verbose

Methods inherited from class java.lang.Object

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

Constructor Details

SoftDeletesRetentionMergePolicy

public SoftDeletesRetentionMergePolicy(String field,
 Supplier<Query> retentionQuerySupplier,
 MergePolicy in)

Creates a new SoftDeletesRetentionMergePolicy

Parameters:

field - the soft deletes field

retentionQuerySupplier - a query supplier for the retention query

in - the wrapped MergePolicy

Method Details

keepFullyDeletedSegment

public boolean keepFullyDeletedSegment(IOSupplier<CodecReader> readerIOSupplier)
                                throws IOException

Description copied from class: MergePolicy

Returns true if the segment represented by the given CodecReader should be keep even if it's fully deleted. This is useful for testing of for instance if the merge policy implements retention policies for soft deletes.

Overrides:

keepFullyDeletedSegment in class FilterMergePolicy

Throws:

IOException

numDeletesToMerge

public int numDeletesToMerge(SegmentCommitInfo info,
 int delCount,
 IOSupplier<CodecReader> readerSupplier)
                      throws IOException

Description copied from class: MergePolicy

Returns the number of deletes that a merge would claim on the given segment. This method will by default return the sum of the del count on disk and the pending delete count. Yet, subclasses that wrap merge readers might modify this to reflect deletes that are carried over to the target segment in the case of soft deletes.

Soft deletes all deletes to survive across merges in order to control when the soft-deleted data is claimed.

Overrides:

numDeletesToMerge in class FilterMergePolicy

Parameters:

info - the segment info that identifies the segment

delCount - the number deleted documents for this segment

readerSupplier - a supplier that allows to obtain a CodecReader for this segment

Throws:

IOException

See Also:

• IndexWriter.softUpdateDocument(Term, Iterable, Field...)
• IndexWriterConfig.setSoftDeletesField(String)