Class LogMergePolicy

This class implements a MergePolicy that tries to merge segments into levels of exponentially increasing size, where each level has fewer segments than the value of the merge factor. Whenever extra segments (beyond the merge factor upper bound) are encountered, all segments within the level are merged. You can get or set the merge factor using MergeFactor and MergeFactor respectively.

This class is abstract and requires a subclass to define the Size(SegmentInfo) method which specifies how a segment's size is determined. LogDocMergePolicy is one subclass that measures size by document count in the segment. LogByteSizeMergePolicy is another subclass that measures size as the total byte size of the file(s) for the segment.

Inheritance

System.Object

MergePolicy

LogMergePolicy

LogByteSizeMergePolicy

LogDocMergePolicy

Inherited Members

MergePolicy.writer

MergePolicy.Close()

MergePolicy.Dispose()

MergePolicy.Dispose(Boolean)

Namespace:

Assembly: Lucene.Net.NetCore.dll

Syntax

public abstract class LogMergePolicy : MergePolicy

Constructors

Name	Description
LogMergePolicy(IndexWriter)

Fields

Name	Description
DEFAULT_MAX_MERGE_DOCS	Default maximum segment size. A segment of this size
DEFAULT_MERGE_FACTOR	Default merge factor, which is how many segments are merged at a time
DEFAULT_NO_CFS_RATIO	Default noCFSRatio. If a merge's size is >= 10% of the index, then we disable compound file for it. See NoCFSRatio
internalCalibrateSizeByDeletes
internalNoCFSRatio
LEVEL_LOG_SPAN	Defines the allowed range of log(size) for each level. A level is computed by taking the max segment log size, minus LEVEL_LOG_SPAN, and finding all segments falling within that range.

Properties

Name	Description
CalibrateSizeByDeletes	Gets or sets whether the segment size should be calibrated by the number of deletes when choosing segments for merge.
MaxMergeDocs	Gets or sets the largest segment (measured by document count) that may be merged with other segments. Determines the largest segment (measured by document count) that may be merged with other segments. Small values (e.g., less than 10,000) are best for interactive indexing, as this limits the length of pauses while indexing to a few seconds. Larger values are best for batched indexing and speedier searches. The default value is . The default merge policy (LogByteSizeMergePolicy) also allows you to set this limit by net size (in MB) of the segment, using MaxMergeMB.
MergeFactor	Gets or sets how often segment indices are merged by addDocument(). With smaller values, less RAM is used while indexing, and searches on unoptimized indices are faster, but indexing speed is slower. With larger values, more RAM is used during indexing, and while searches on unoptimized indices are slower, indexing is faster. Thus larger values (> 10) are best for batch index creation, and smaller values (< 10) for indices that are interactively maintained.
NoCFSRatio

Methods

Name	Description
FindMerges(SegmentInfos)	Checks if any merges are now necessary and returns a MergePolicy.MergeSpecification if so. A merge is necessary when there are more than MergeFactor segments at a given level. When multiple levels have too many segments, this method will return multiple merges, allowing the MergeScheduler to use concurrency.
FindMergesForOptimize(SegmentInfos, Int32, ISet<SegmentInfo>)	Returns the merges necessary to optimize the index. This merge policy defines "optimized" to mean only one segment in the index, where that segment has no deletions pending nor separate norms, and it is in compound file format if the current useCompoundFile setting is true. This method returns multiple merges (mergeFactor at a time) so the MergeScheduler in use may make use of concurrency.
FindMergesToExpungeDeletes(SegmentInfos)	Finds merges necessary to expunge all deletes from the index. We simply merge adjacent segments that have deletes, up to mergeFactor at a time.
GetUseCompoundDocStore()	Returns true if newly flushed and newly merge doc store segment files (term vectors and stored fields)
GetUseCompoundFile()
MakeOneMerge(SegmentInfos, SegmentInfos)
SetUseCompoundDocStore(Boolean)	Sets whether compound file format should be used for newly flushed and newly merged doc store segment files (term vectors and stored fields).
SetUseCompoundFile(Boolean)	Gets or sets whether compound file format should be used for newly flushed and newly merged segments.
Size(SegmentInfo)
SizeBytes(SegmentInfo)
SizeDocs(SegmentInfo)
UseCompoundDocStore(SegmentInfos)
UseCompoundFile(SegmentInfos, SegmentInfo)
Verbose()