org.apache.lucene.codecs.idversion

Class IDVersionPostingsFormat

java.lang.Object

org.apache.lucene.codecs.PostingsFormat

org.apache.lucene.codecs.idversion.IDVersionPostingsFormat

All Implemented Interfaces:

NamedSPILoader.NamedSPI

public class IDVersionPostingsFormat
extends PostingsFormat

A PostingsFormat optimized for primary-key (ID) fields that also record a version (long) for each ID, delivered as a payload created by longToBytes(long, org.apache.lucene.util.BytesRef) during indexing. At search time, the TermsEnum implementation IDVersionSegmentTermsEnum enables fast (using only the terms index when possible) lookup for whether a given ID was previously indexed with version > N (see IDVersionSegmentTermsEnum.seekExact(BytesRef,long).

This is most effective if the app assigns monotonically increasing global version to each indexed doc. Then, during indexing, use IDVersionSegmentTermsEnum.seekExact(BytesRef,long) (along with LiveFieldValues) to decide whether the document you are about to index was already indexed with a higher version, and skip it if so.

The field is effectively indexed as DOCS_ONLY and the docID is pulsed into the terms dictionary, but the user must feed in the version as a payload on the first token.

NOTE: term vectors cannot be indexed with this field (not that you should really ever want to do this).

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

Field Summary

Fields

Modifier and Type	Field and Description
static long	MAX_VERSION version must be <= this, because we encode with ZigZag.
static long	MIN_VERSION version must be >= this.

Fields inherited from class org.apache.lucene.codecs.PostingsFormat

EMPTY

Constructor Summary

Constructors

Constructor and Description
IDVersionPostingsFormat()
IDVersionPostingsFormat(int minTermsInBlock, int maxTermsInBlock)

Method Summary

Methods

Modifier and Type	Method and Description
static long	bytesToLong(BytesRef bytes)
FieldsConsumer	fieldsConsumer(SegmentWriteState state)
FieldsProducer	fieldsProducer(SegmentReadState state)
static void	longToBytes(long v, BytesRef bytes)

Methods inherited from class org.apache.lucene.codecs.PostingsFormat

availablePostingsFormats, forName, getName, reloadPostingsFormats, toString

Methods inherited from class java.lang.Object

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

Field Detail

MIN_VERSION

public static final long MIN_VERSION

version must be >= this.

See Also:

Constant Field Values

MAX_VERSION

public static final long MAX_VERSION

version must be <= this, because we encode with ZigZag.

See Also:

Constant Field Values

Constructor Detail

IDVersionPostingsFormat

public IDVersionPostingsFormat()

IDVersionPostingsFormat

public IDVersionPostingsFormat(int minTermsInBlock,
                       int maxTermsInBlock)

Method Detail

fieldsConsumer

public FieldsConsumer fieldsConsumer(SegmentWriteState state)
                              throws IOException

Specified by:

fieldsConsumer in class PostingsFormat

Throws:

IOException

fieldsProducer

public FieldsProducer fieldsProducer(SegmentReadState state)
                              throws IOException

Specified by:

fieldsProducer in class PostingsFormat

Throws:

IOException

bytesToLong

public static long bytesToLong(BytesRef bytes)

longToBytes

public static void longToBytes(long v,
               BytesRef bytes)