org.apache.lucene.codecs.memory

Class DirectPostingsFormat

java.lang.Object

org.apache.lucene.codecs.PostingsFormat

org.apache.lucene.codecs.memory.DirectPostingsFormat

All Implemented Interfaces:

NamedSPILoader.NamedSPI

public final class DirectPostingsFormat
extends PostingsFormat

Wraps Lucene84PostingsFormat format for on-disk storage, but then at read time loads and stores all terms and 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 TermsEnum.ord() and TermsEnum.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.

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

Field Summary

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

EMPTY

Constructor Summary

Constructors

Constructor and Description
DirectPostingsFormat()
DirectPostingsFormat(int minSkipCount, int lowFreqCutoff) minSkipCount is how many terms in a row must have the same prefix before we put a skip pointer down.

Method Summary

Modifier and Type	Method and Description
FieldsConsumer	fieldsConsumer(SegmentWriteState state)
FieldsProducer	fieldsProducer(SegmentReadState state)

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

Constructor Detail

DirectPostingsFormat

public DirectPostingsFormat()

DirectPostingsFormat

public DirectPostingsFormat(int minSkipCount,
                            int lowFreqCutoff)

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

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