er.neo4jadaptor.query.lucene

Class LuceneOptimizer<Type extends org.neo4j.graphdb.PropertyContainer>

java.lang.Object

er.neo4jadaptor.query.lucene.LuceneOptimizer<Type>

Type Parameters:

Type -

public class LuceneOptimizer<Type extends org.neo4j.graphdb.PropertyContainer>
extends Object

Consider EOQualifier:

 (((service.dvbOriginalNetworkId = 1536) and (service.dvbTransportStreamId = 2069) and (service.dvbServiceId = 19322)) and (endDateTime >= (com.webobjects.foundation.NSTimestamp)'2012-06-07 04:00:00 Etc/GMT'))
 

LuceneQueryConverter doesn't support relationships so it would convert it to:

 +(+(+#_type:WEPGEvent +#_type:WEPGEvent +#_type:WEPGEvent) +endDateTime:[2012060706:00:00:000 TO ZZZZ]) +#_type:WEPGEvent
 

which would return more results than actually matching the original query. We could optimize lucene query by first searching for services matching

 
 dvbOriginalNetworkId = 1536 and dvbTransportStreamId = 2069 and dvbServiceId = 19322
 

and then replace ((service.dvbOriginalNetworkId = 1536) and (service.dvbTransportStreamId = 2069) and (service.dvbServiceId = 19322)) part with matching service IDs, so we could get in result something like: +(+(+(+#_type:WEPGEvent +#_type:WEPGEvent +#_type:WEPGEvent) +endDateTime:[2012060706:00:00:000 TO ZZZZ]) +#_type:WEPGEvent) +(serviceId:00000000000000002026) instead.

Due to the fact that optimization process makes another Lucene query which has a around-constant overhead, we perform optimization attempt only if the initial number of results exceeds threshold of 1000. TODO: refactor

Author:

Jedrzej Sobanski

Field Summary

Fields

Modifier and Type	Field and Description
static int	OPTIMIZATION_TRESHOLD Perform optimization attempt only if there are more then this many results.

Constructor Summary

Constructors

Constructor and Description
LuceneOptimizer(org.neo4j.graphdb.index.Index<Type> index)

Method Summary

Modifier and Type	Method and Description
static boolean	canBeOptimized(org.neo4j.graphdb.index.IndexHits<? extends org.neo4j.graphdb.PropertyContainer> hits, EOQualifier qualifier)
Results<Type>	optimize(org.apache.lucene.search.Query q, EOEntity entity, EOQualifier qualifier)

Methods inherited from class java.lang.Object

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

Field Detail

OPTIMIZATION_TRESHOLD

public static final int OPTIMIZATION_TRESHOLD

Perform optimization attempt only if there are more then this many results.

See Also:

Constant Field Values

Constructor Detail

LuceneOptimizer

public LuceneOptimizer(org.neo4j.graphdb.index.Index<Type> index)

Method Detail

canBeOptimized

public static boolean canBeOptimized(org.neo4j.graphdb.index.IndexHits<? extends org.neo4j.graphdb.PropertyContainer> hits,
                                     EOQualifier qualifier)

optimize

public Results<Type> optimize(org.apache.lucene.search.Query q,
                              EOEntity entity,
                              EOQualifier qualifier)