Package org.apache.lucene.facet.taxonomy

Class CachedOrdinalsReader

java.lang.Object

org.apache.lucene.facet.taxonomy.OrdinalsReader

org.apache.lucene.facet.taxonomy.CachedOrdinalsReader

public class CachedOrdinalsReader
extends OrdinalsReader

A per-segment cache of documents' facet ordinals. Every CachedOrdinalsReader.CachedOrds holds the ordinals in a raw int[], and therefore consumes as much RAM as the total number of ordinals found in the segment, but saves the CPU cost of decoding ordinals during facet counting.

NOTE: every CachedOrdinalsReader.CachedOrds is limited to 2.1B total ordinals. If that is a limitation for you then consider limiting the segment size to fewer documents, or use an alternative cache which pages through the category ordinals.

NOTE: when using this cache, it is advised to use a DocValuesFormat that does not cache the data in memory, at least for the category lists fields, or otherwise you'll be doing double-caching.

NOTE: create one instance of this and re-use it for all facet implementations (the cache is per-instance, not static).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	CachedOrdinalsReader.CachedOrds	Holds the cached ordinals in two paralel int[] arrays.

Nested classes/interfaces inherited from class org.apache.lucene.facet.taxonomy.OrdinalsReader

OrdinalsReader.OrdinalsSegmentReader

Constructor Summary

Constructors

Constructor	Description
CachedOrdinalsReader(OrdinalsReader source)	Sole constructor.

Method Summary

Modifier and Type	Method	Description
java.lang.String	getIndexFieldName()	Returns the indexed field name this OrdinalsReader is reading from.
OrdinalsReader.OrdinalsSegmentReader	getReader(AtomicReaderContext context)	Set current atomic reader.
long	ramBytesUsed()	How many bytes is this cache using?

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CachedOrdinalsReader

public CachedOrdinalsReader(OrdinalsReader source)

Sole constructor.

Method Detail

getIndexFieldName

public java.lang.String getIndexFieldName()

Description copied from class: OrdinalsReader

Returns the indexed field name this OrdinalsReader is reading from.

Specified by:

getIndexFieldName in class OrdinalsReader

getReader

public OrdinalsReader.OrdinalsSegmentReader getReader(AtomicReaderContext context)
                                               throws java.io.IOException

Description copied from class: OrdinalsReader

Set current atomic reader.

Specified by:

getReader in class OrdinalsReader

Throws:

java.io.IOException

ramBytesUsed

public long ramBytesUsed()

How many bytes is this cache using?