org.apache.lucene.facet.search

Class OrdinalsCache

java.lang.Object

org.apache.lucene.facet.search.OrdinalsCache

public class OrdinalsCache
extends Object

A per-segment cache of documents' category ordinals. Every OrdinalsCache.CachedOrds holds the ordinals in a raw int[], and therefore consumes as much RAM as the total number of ordinals found in the segment.

NOTE: every OrdinalsCache.CachedOrds is limited to 2.1B total ordinals. If that is a limitation for you then consider limiting the segment size to less 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.

Nested Class Summary

Nested Classes

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

Constructor Summary

Constructors

Constructor and Description
OrdinalsCache()

Method Summary

Methods

Modifier and Type	Method and Description
static void	clear() Clears all entries from the cache.
static OrdinalsCache.CachedOrds	getCachedOrds(AtomicReaderContext context, CategoryListParams clp) Returns the OrdinalsCache.CachedOrds relevant to the given AtomicReaderContext, or null if there is no BinaryDocValues in this reader for the requested CategoryListParams.field.
static long	ramBytesUsed() Returns how many bytes the static ords cache is consuming.

Methods inherited from class java.lang.Object

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

Constructor Detail

OrdinalsCache

public OrdinalsCache()

Method Detail

getCachedOrds

public static OrdinalsCache.CachedOrds getCachedOrds(AtomicReaderContext context,
                                     CategoryListParams clp)
                                              throws IOException

Returns the OrdinalsCache.CachedOrds relevant to the given AtomicReaderContext, or null if there is no BinaryDocValues in this reader for the requested CategoryListParams.field.

Throws:

IOException

ramBytesUsed

public static long ramBytesUsed()

Returns how many bytes the static ords cache is consuming.

clear

public static void clear()

Clears all entries from the cache.