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Speed up named queries. #18470 

Named queries have a performance bug when they are used with expensive queries
that need to perform a lot of work up-front like fuzzy or range queries
(including with points). The reason is that they currently re-create the weight
and scorer for every hit. Instead we should create weights exactly once and
use a single Scorer for all documents that are on the same segment.
This commit is contained in:
Adrien Grand 2016-05-19 18:38:35 +02:00
parent 89a57bce5a
commit cb2cfdd9c0
1 changed files with 53 additions and 38 deletions
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87
core/src/main/java/org/elasticsearch/search/fetch/matchedqueries/MatchedQueriesFetchSubPhase.java
View File

@ -18,11 +18,14 @@
*/
package org.elasticsearch.search.fetch.matchedqueries;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.index.ReaderUtil;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.TwoPhaseIterator;
import org.apache.lucene.search.Weight;
import org.apache.lucene.util.Bits;
import org.elasticsearch.ExceptionsHelper;
import org.elasticsearch.common.lucene.Lucene;
import org.elasticsearch.search.SearchParseElement;
import org.elasticsearch.search.fetch.FetchSubPhase;
import org.elasticsearch.search.internal.InternalSearchHit;
@ -31,6 +34,8 @@ import org.elasticsearch.search.internal.SearchContext.Lifetime;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
@ -48,58 +53,68 @@ public class MatchedQueriesFetchSubPhase implements FetchSubPhase {
@Override
public boolean hitsExecutionNeeded(SearchContext context) {
return false;
return true; // we short-circuit in hitsExecute
}
@Override
public void hitsExecute(SearchContext context, InternalSearchHit[] hits) {
if (hits.length == 0) {
return;
}
hits = hits.clone(); // don't modify the incoming hits
Arrays.sort(hits, (a, b) -> Integer.compare(a.docId(), b.docId()));
@SuppressWarnings("unchecked")
List<String>[] matchedQueries = new List[hits.length];
for (int i = 0; i < matchedQueries.length; ++i) {
matchedQueries[i] = new ArrayList<>();
}
@Override
public boolean hitExecutionNeeded(SearchContext context) {
return !context.parsedQuery().namedFilters().isEmpty()
|| (context.parsedPostFilter() !=null && !context.parsedPostFilter().namedFilters().isEmpty());
Map<String, Query> namedQueries = new HashMap<>(context.parsedQuery().namedFilters());
if (context.parsedPostFilter() != null) {
namedQueries.putAll(context.parsedPostFilter().namedFilters());
}
@Override
public void hitExecute(SearchContext context, HitContext hitContext) {
List<String> matchedQueries = new ArrayList<>(2);
try {
addMatchedQueries(hitContext, context.parsedQuery().namedFilters(), matchedQueries);
if (context.parsedPostFilter() != null) {
addMatchedQueries(hitContext, context.parsedPostFilter().namedFilters(), matchedQueries);
for (Map.Entry<String, Query> entry : namedQueries.entrySet()) {
String name = entry.getKey();
Query query = entry.getValue();
int readerIndex = -1;
int docBase = -1;
Weight weight = context.searcher().createNormalizedWeight(query, false);
Bits matchingDocs = null;
for (int i = 0; i < hits.length; ++i) {
InternalSearchHit hit = hits[i];
int hitReaderIndex = ReaderUtil.subIndex(hit.docId(), context.searcher().getIndexReader().leaves());
if (readerIndex != hitReaderIndex) {
readerIndex = hitReaderIndex;
LeafReaderContext ctx = context.searcher().getIndexReader().leaves().get(readerIndex);
docBase = ctx.docBase;
// scorers can be costly to create, so reuse them across docs of the same segment
Scorer scorer = weight.scorer(ctx);
matchingDocs = Lucene.asSequentialAccessBits(ctx.reader().maxDoc(), scorer);
}
if (matchingDocs.get(hit.docId() - docBase)) {
matchedQueries[i].add(name);
}
}
}
for (int i = 0; i < hits.length; ++i) {
hits[i].matchedQueries(matchedQueries[i].toArray(new String[0]));
}
} catch (IOException e) {
throw ExceptionsHelper.convertToElastic(e);
} finally {
SearchContext.current().clearReleasables(Lifetime.COLLECTION);
}
hitContext.hit().matchedQueries(matchedQueries.toArray(new String[matchedQueries.size()]));
}
private void addMatchedQueries(HitContext hitContext, Map<String, Query> namedQueries, List<String> matchedQueries) throws IOException {
for (Map.Entry<String, Query> entry : namedQueries.entrySet()) {
String name = entry.getKey();
Query filter = entry.getValue();
@Override
public boolean hitExecutionNeeded(SearchContext context) {
return false;
}
final Weight weight = hitContext.topLevelSearcher().createNormalizedWeight(filter, false);
final Scorer scorer = weight.scorer(hitContext.readerContext());
if (scorer == null) {
continue;
}
final TwoPhaseIterator twoPhase = scorer.twoPhaseIterator();
if (twoPhase == null) {
if (scorer.iterator().advance(hitContext.docId()) == hitContext.docId()) {
matchedQueries.add(name);
}
} else {
if (twoPhase.approximation().advance(hitContext.docId()) == hitContext.docId() && twoPhase.matches()) {
matchedQueries.add(name);
}
}
}
@Override
public void hitExecute(SearchContext context, HitContext hitContext) {
// we do everything in hitsExecute
}
}