Class UpgradeIndexMergePolicy

This MergePolicy is used for upgrading all existing segments of an index when calling ForceMerge(Int32). All other methods delegate to the base MergePolicy given to the constructor. This allows for an as-cheap-as possible upgrade of an older index by only upgrading segments that are created by previous Lucene versions. ForceMerge does no longer really merge; it is just used to "ForceMerge" older segment versions away.

In general one would use IndexUpgrader, but for a fully customizeable upgrade, you can use this like any other MergePolicy and call ForceMerge(Int32):

    IndexWriterConfig iwc = new IndexWriterConfig(LuceneVersion.LUCENE_XX, new KeywordAnalyzer());
    iwc.MergePolicy = new UpgradeIndexMergePolicy(iwc.MergePolicy);
    using (IndexWriter w = new IndexWriter(dir, iwc))
    {
        w.ForceMerge(1);
    }

Warning: this merge policy may reorder documents if the index was partially upgraded before calling ForceMerge(Int32) (e.g., documents were added). If your application relies on "monotonicity" of doc IDs (which means that the order in which the documents were added to the index is preserved), do a ForceMerge(1) instead. Please note, the delegate MergePolicy may also reorder documents.

This is a Lucene.NET EXPERIMENTAL API, use at your own risk
Inheritance
System.Object
MergePolicy
UpgradeIndexMergePolicy
Inherited Members
Namespace: Lucene.Net.Index
Assembly: Lucene.Net.dll
Syntax
public class UpgradeIndexMergePolicy : MergePolicy

Constructors

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UpgradeIndexMergePolicy(MergePolicy)

Wrap the given MergePolicy and intercept ForceMerge(Int32) requests to only upgrade segments written with previous Lucene versions.

Declaration
public UpgradeIndexMergePolicy(MergePolicy base)
Parameters
Type Name Description
MergePolicy base

Fields

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m_base

Wrapped MergePolicy.

Declaration
protected readonly MergePolicy m_base
Field Value
Type Description
MergePolicy

Methods

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Dispose(Boolean)

Declaration
protected override void Dispose(bool disposing)
Parameters
Type Name Description
System.Boolean disposing
Overrides
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FindForcedDeletesMerges(SegmentInfos)

Declaration
public override MergePolicy.MergeSpecification FindForcedDeletesMerges(SegmentInfos segmentInfos)
Parameters
Type Name Description
SegmentInfos segmentInfos
Returns
Type Description
MergePolicy.MergeSpecification
Overrides
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FindForcedMerges(SegmentInfos, Int32, IDictionary<SegmentCommitInfo, Nullable<Boolean>>)

Declaration
public override MergePolicy.MergeSpecification FindForcedMerges(SegmentInfos segmentInfos, int maxSegmentCount, IDictionary<SegmentCommitInfo, bool?> segmentsToMerge)
Parameters
Type Name Description
SegmentInfos segmentInfos
System.Int32 maxSegmentCount
IDictionary<SegmentCommitInfo, System.Nullable<System.Boolean>> segmentsToMerge
Returns
Type Description
MergePolicy.MergeSpecification
Overrides
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FindMerges(MergeTrigger, SegmentInfos)

Declaration
public override MergePolicy.MergeSpecification FindMerges(MergeTrigger mergeTrigger, SegmentInfos segmentInfos)
Parameters
Type Name Description
MergeTrigger mergeTrigger
SegmentInfos segmentInfos
Returns
Type Description
MergePolicy.MergeSpecification
Overrides
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SetIndexWriter(IndexWriter)

Declaration
public override void SetIndexWriter(IndexWriter writer)
Parameters
Type Name Description
IndexWriter writer
Overrides
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ShouldUpgradeSegment(SegmentCommitInfo)

Returns true if the given segment should be upgraded. The default implementation will return !Constants.LUCENE_MAIN_VERSION.Equals(si.Info.Version, StringComparison.Ordinal), so all segments created with a different version number than this Lucene version will get upgraded.

Declaration
protected virtual bool ShouldUpgradeSegment(SegmentCommitInfo si)
Parameters
Type Name Description
SegmentCommitInfo si
Returns
Type Description
System.Boolean
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ToString()

Declaration
public override string ToString()
Returns
Type Description
System.String
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UseCompoundFile(SegmentInfos, SegmentCommitInfo)

Declaration
public override bool UseCompoundFile(SegmentInfos segments, SegmentCommitInfo newSegment)
Parameters
Type Name Description
SegmentInfos segments
SegmentCommitInfo newSegment
Returns
Type Description
System.Boolean
Overrides

See Also