org.elasticsearch.indices.cache.request

Class IndicesRequestCache

java.lang.Object

org.elasticsearch.common.component.AbstractComponent

org.elasticsearch.indices.cache.request.IndicesRequestCache

All Implemented Interfaces:

com.google.common.cache.RemovalListener<IndicesRequestCache.Key,IndicesRequestCache.Value>

public class IndicesRequestCache
extends AbstractComponent
implements com.google.common.cache.RemovalListener<IndicesRequestCache.Key,IndicesRequestCache.Value>

The indices request cache allows to cache a shard level request stage responses, helping with improving similar requests that are potentially expensive (because of aggs for example). The cache is fully coherent with the semantics of NRT (the index reader version is part of the cache key), and relies on size based eviction to evict old reader associated cache entries as well as scheduler reaper to clean readers that are no longer used or closed shards.

Currently, the cache is only enabled for count requests, and can only be opted in on an index level setting that can be dynamically changed and defaults to false.

There are still several TODOs left in this class, some easily addressable, some more complex, but the support is functional.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	IndicesRequestCache.Key
static class	IndicesRequestCache.Value

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEPRECATED_INDEX_CACHE_REQUEST_ENABLED Deprecated.
static String	DEPRECATED_INDICES_CACHE_QUERY_SIZE Deprecated.
static String	INDEX_CACHE_REQUEST_ENABLED A setting to enable or disable request caching on an index level.
static String	INDICES_CACHE_QUERY_CONCURRENCY_LEVEL
static String	INDICES_CACHE_QUERY_EXPIRE
static String	INDICES_CACHE_QUERY_SIZE
static String	INDICES_CACHE_REQUEST_CLEAN_INTERVAL

Fields inherited from class org.elasticsearch.common.component.AbstractComponent

deprecationLogger, logger, settings

Constructor Summary

Constructors

Constructor and Description
IndicesRequestCache(Settings settings, ClusterService clusterService, ThreadPool threadPool)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	canCache(ShardSearchRequest request, SearchContext context) Can the shard request be cached at all?
void	clear(IndexShard shard)
void	close()
void	loadIntoContext(ShardSearchRequest request, SearchContext context, QueryPhase queryPhase) Loads the cache result, computing it if needed by executing the query phase and otherwise deserializing the cached value into the context's query result.
void	onRemoval(com.google.common.cache.RemovalNotification<IndicesRequestCache.Key,IndicesRequestCache.Value> notification)

Methods inherited from class org.elasticsearch.common.component.AbstractComponent

logDeprecatedSetting, logRemovedSetting, nodeName

Methods inherited from class java.lang.Object

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

Field Detail

INDEX_CACHE_REQUEST_ENABLED

public static final String INDEX_CACHE_REQUEST_ENABLED

A setting to enable or disable request caching on an index level. Its dynamic by default since we are checking on the cluster state IndexMetaData always.

See Also:

Constant Field Values

DEPRECATED_INDEX_CACHE_REQUEST_ENABLED

@Deprecated
public static final String DEPRECATED_INDEX_CACHE_REQUEST_ENABLED

Deprecated.

See Also:

Constant Field Values

INDICES_CACHE_REQUEST_CLEAN_INTERVAL

public static final String INDICES_CACHE_REQUEST_CLEAN_INTERVAL

See Also:

Constant Field Values

INDICES_CACHE_QUERY_SIZE

public static final String INDICES_CACHE_QUERY_SIZE

See Also:

Constant Field Values

DEPRECATED_INDICES_CACHE_QUERY_SIZE

@Deprecated
public static final String DEPRECATED_INDICES_CACHE_QUERY_SIZE

Deprecated.

See Also:

Constant Field Values

INDICES_CACHE_QUERY_EXPIRE

public static final String INDICES_CACHE_QUERY_EXPIRE

See Also:

Constant Field Values

INDICES_CACHE_QUERY_CONCURRENCY_LEVEL

public static final String INDICES_CACHE_QUERY_CONCURRENCY_LEVEL

See Also:

Constant Field Values

Constructor Detail

IndicesRequestCache

@Inject
public IndicesRequestCache(Settings settings,
                          ClusterService clusterService,
                          ThreadPool threadPool)

Method Detail

close

public void close()

clear

public void clear(IndexShard shard)

onRemoval

public void onRemoval(com.google.common.cache.RemovalNotification<IndicesRequestCache.Key,IndicesRequestCache.Value> notification)

Specified by:

onRemoval in interface com.google.common.cache.RemovalListener<IndicesRequestCache.Key,IndicesRequestCache.Value>

canCache

public boolean canCache(ShardSearchRequest request,
               SearchContext context)

Can the shard request be cached at all?

loadIntoContext

public void loadIntoContext(ShardSearchRequest request,
                   SearchContext context,
                   QueryPhase queryPhase)
                     throws Exception

Loads the cache result, computing it if needed by executing the query phase and otherwise deserializing the cached value into the context's query result. The combination of load + compute allows to have a single load operation that will cause other requests with the same key to wait till its loaded an reuse the same cache.

Throws:

Exception