org.apache.solr.search.stats

Class StatsCache

java.lang.Object

org.apache.solr.search.stats.StatsCache

All Implemented Interfaces:

PluginInfoInitialized

Direct Known Subclasses:

ExactStatsCache, LocalStatsCache

public abstract class StatsCache
extends Object
implements PluginInfoInitialized

This class represents a cache of global document frequency information for selected terms. This information is periodically updated from all shards, either through scheduled events of some kind, or on every request when there is no global stats available for terms involved in the query (or if this information is stale due to changes in the shards).

There are instances of this class at the aggregator node (where the partial data from shards is aggregated), and on each core involved in a shard request (where this data is maintained and updated from the central cache).

Field Summary

Fields

Modifier and Type	Field and Description
static String	COL_STATS_KEY Value of CollectionStats.
static String	TERM_STATS_KEY Map of terms and TermStats.
static String	TERMS_KEY List of terms in the query.

Constructor Summary

Constructors

Constructor and Description
StatsCache()

Method Summary

Modifier and Type	Method and Description
abstract StatsSource	get(SolrQueryRequest req) Prepare local StatsSource to provide stats information to perform local scoring (to be precise, to build a local Weight from the query).
abstract void	mergeToGlobalStats(SolrQueryRequest req, List<ShardResponse> responses) Process shard responses that contain partial local stats.
abstract void	receiveGlobalStats(SolrQueryRequest req) Receive global stats data from the master and update a local cache of stats with this global data.
abstract ShardRequest	retrieveStatsRequest(ResponseBuilder rb) Creates a ShardRequest to retrieve per-shard stats related to the current query and the current state of the requester's StatsCache.
abstract void	returnLocalStats(ResponseBuilder rb, SolrIndexSearcher searcher) Prepare a local (from the local shard) response to a "retrieve stats" shard request.
abstract void	sendGlobalStats(ResponseBuilder rb, ShardRequest outgoing) Prepare global stats data to be sent out to shards in this request.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.solr.util.plugin.PluginInfoInitialized

init

Field Detail

TERM_STATS_KEY

public static final String TERM_STATS_KEY

Map of terms and TermStats.

See Also:

Constant Field Values

COL_STATS_KEY

public static final String COL_STATS_KEY

Value of CollectionStats.

See Also:

Constant Field Values

TERMS_KEY

public static final String TERMS_KEY

List of terms in the query.

See Also:

Constant Field Values

Constructor Detail

StatsCache

public StatsCache()

Method Detail

retrieveStatsRequest

public abstract ShardRequest retrieveStatsRequest(ResponseBuilder rb)

Creates a ShardRequest to retrieve per-shard stats related to the current query and the current state of the requester's StatsCache.

Parameters:

rb - contains current request

Returns:

shard request to retrieve stats for terms in the current request, or null if no additional request is needed (e.g. if the information in global cache is already sufficient to satisfy this request).

returnLocalStats

public abstract void returnLocalStats(ResponseBuilder rb,
                                      SolrIndexSearcher searcher)

Prepare a local (from the local shard) response to a "retrieve stats" shard request.

Parameters:

rb - response builder

searcher - current local searcher

mergeToGlobalStats

public abstract void mergeToGlobalStats(SolrQueryRequest req,
                                        List<ShardResponse> responses)

Process shard responses that contain partial local stats. Usually this entails combining per-shard stats for each term.

Parameters:

req - query request

responses - responses from shards containing local stats for each shard

receiveGlobalStats

public abstract void receiveGlobalStats(SolrQueryRequest req)

Receive global stats data from the master and update a local cache of stats with this global data. This event occurs either as a separate request, or together with the regular query request, in which case this method is called first, before preparing a QueryCommand to be submitted to the local SolrIndexSearcher.

Parameters:

req - query request with global stats data

sendGlobalStats

public abstract void sendGlobalStats(ResponseBuilder rb,
                                     ShardRequest outgoing)

Prepare global stats data to be sent out to shards in this request.

Parameters:

rb - response builder

outgoing - shard request to be sent

get

public abstract StatsSource get(SolrQueryRequest req)

Prepare local StatsSource to provide stats information to perform local scoring (to be precise, to build a local Weight from the query).

Parameters:

req - query request

Returns:

an instance of StatsSource to use in creating a query Weight