Class DirectPostingsFormat

Wraps Lucene.Net.Codecs.Lucene41.Lucene41PostingsFormat format for on-disk storage, but then at read time loads and stores all terms & postings directly in RAM as byte[], int[].

WARNING: This is exceptionally RAM intensive: it makes no effort to compress the postings data, storing terms as separate byte[] and postings as separate int[], but as a result it gives substantial increase in search performance.

This postings format supports Lucene.Net.Index.TermsEnum.Ord and SeekExact(long).

Because this holds all term bytes as a single byte[], you cannot have more than 2.1GB worth of term bytes in a single segment.

Note

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

Inheritance

object

PostingsFormat

DirectPostingsFormat

Inherited Members

PostingsFormat.EMPTY

PostingsFormat.SetPostingsFormatFactory(IPostingsFormatFactory)

PostingsFormat.GetPostingsFormatFactory()

PostingsFormat.Name

PostingsFormat.ToString()

PostingsFormat.ForName(string)

PostingsFormat.AvailablePostingsFormats

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

Namespace: Lucene.Net.Codecs.Memory

Assembly: Lucene.Net.Codecs.dll

Syntax

[PostingsFormatName("Direct")]
public sealed class DirectPostingsFormat : PostingsFormat

Constructors

DirectPostingsFormat()

Wraps Lucene.Net.Codecs.Lucene41.Lucene41PostingsFormat format for on-disk storage, but then at read time loads and stores all terms & postings directly in RAM as byte[], int[].

WARNING: This is exceptionally RAM intensive: it makes no effort to compress the postings data, storing terms as separate byte[] and postings as separate int[], but as a result it gives substantial increase in search performance.

This postings format supports Lucene.Net.Index.TermsEnum.Ord and SeekExact(long).

Because this holds all term bytes as a single byte[], you cannot have more than 2.1GB worth of term bytes in a single segment.

Note

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

Declaration

public DirectPostingsFormat()

DirectPostingsFormat(int, int)

minSkipCount is how many terms in a row must have the same prefix before we put a skip pointer down. Terms with docFreq less than or equal lowFreqCutoff will use a single int[] to hold all docs, freqs, position and offsets; terms with higher docFreq will use separate arrays.

Declaration

public DirectPostingsFormat(int minSkipCount, int lowFreqCutoff)

Parameters

Type	Name	Description
int	minSkipCount
int	lowFreqCutoff

Methods

FieldsConsumer(SegmentWriteState)

Writes a new segment.

Declaration

public override FieldsConsumer FieldsConsumer(SegmentWriteState state)

Parameters

Type	Name	Description
SegmentWriteState	state

Returns

Type	Description
FieldsConsumer

Overrides

Lucene.Net.Codecs.PostingsFormat.FieldsConsumer(Lucene.Net.Index.SegmentWriteState)

FieldsProducer(SegmentReadState)

Reads a segment. NOTE: by the time this call returns, it must hold open any files it will need to use; else, those files may be deleted. Additionally, required files may be deleted during the execution of this call before there is a chance to open them. Under these circumstances an IOException should be thrown by the implementation. IOExceptions are expected and will automatically cause a retry of the segment opening logic with the newly revised segments.

Declaration

public override FieldsProducer FieldsProducer(SegmentReadState state)

Parameters

Type	Name	Description
SegmentReadState	state

Returns

Type	Description
FieldsProducer

Overrides

Lucene.Net.Codecs.PostingsFormat.FieldsProducer(Lucene.Net.Index.SegmentReadState)