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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you under
* the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.search.aggregations.metrics.tophits;
import com.carrotsearch.hppc.LongObjectHashMap;
import com.carrotsearch.hppc.cursors.ObjectCursor;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.search.FieldDoc;
import org.apache.lucene.search.LeafCollector;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.search.TopDocsCollector;
import org.apache.lucene.search.TopFieldCollector;
import org.apache.lucene.search.TopFieldDocs;
import org.apache.lucene.search.TopScoreDocCollector;
import org.elasticsearch.ElasticsearchException;
import org.elasticsearch.common.lease.Releasables;
import org.elasticsearch.common.lucene.Lucene;
import org.elasticsearch.common.util.LongObjectPagedHashMap;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.Aggregator;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.LeafBucketCollector;
import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
import org.elasticsearch.search.aggregations.metrics.MetricsAggregator;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
import org.elasticsearch.search.fetch.FetchPhase;
import org.elasticsearch.search.fetch.FetchSearchResult;
import org.elasticsearch.search.internal.SearchContext;
import org.elasticsearch.search.internal.SubSearchContext;
import org.elasticsearch.search.rescore.RescoreContext;
import org.elasticsearch.search.sort.SortAndFormats;
import java.io.IOException;
import java.util.List;
import java.util.Map;
public class TopHitsAggregator extends MetricsAggregator {
private final FetchPhase fetchPhase;
private final SubSearchContext subSearchContext;
private final LongObjectPagedHashMap> topDocsCollectors;
TopHitsAggregator(FetchPhase fetchPhase, SubSearchContext subSearchContext, String name, SearchContext context,
Aggregator parent, List pipelineAggregators, Map metaData) throws IOException {
super(name, context, parent, pipelineAggregators, metaData);
this.fetchPhase = fetchPhase;
topDocsCollectors = new LongObjectPagedHashMap<>(1, context.bigArrays());
this.subSearchContext = subSearchContext;
}
@Override
public boolean needsScores() {
SortAndFormats sort = subSearchContext.sort();
if (sort != null) {
return sort.sort.needsScores() || subSearchContext.trackScores();
} else {
// sort by score
return true;
}
}
@Override
public LeafBucketCollector getLeafCollector(LeafReaderContext ctx, LeafBucketCollector sub) throws IOException {
// Create leaf collectors here instead of at the aggregator level. Otherwise in case this collector get invoked
// when post collecting then we have already replaced the leaf readers on the aggregator level have already been
// replaced with the next leaf readers and then post collection pushes docids of the previous segement, which
// then causes assertions to trip or incorrect top docs to be computed.
final LongObjectHashMap leafCollectors = new LongObjectHashMap<>(1);
return new LeafBucketCollectorBase(sub, null) {
Scorer scorer;
@Override
public void setScorer(Scorer scorer) throws IOException {
this.scorer = scorer;
super.setScorer(scorer);
for (ObjectCursor cursor : leafCollectors.values()) {
cursor.value.setScorer(scorer);
}
}
@Override
public void collect(int docId, long bucket) throws IOException {
TopDocsCollector topDocsCollector = topDocsCollectors.get(bucket);
if (topDocsCollector == null) {
SortAndFormats sort = subSearchContext.sort();
int topN = subSearchContext.from() + subSearchContext.size();
if (sort == null) {
for (RescoreContext rescoreContext : context.rescore()) {
topN = Math.max(rescoreContext.getWindowSize(), topN);
}
}
// In the QueryPhase we don't need this protection, because it is build into the IndexSearcher,
// but here we create collectors ourselves and we need prevent OOM because of crazy an offset and size.
topN = Math.min(topN, subSearchContext.searcher().getIndexReader().maxDoc());
if (sort == null) {
topDocsCollector = TopScoreDocCollector.create(topN);
} else {
// TODO: can we pass trackTotalHits=subSearchContext.trackTotalHits(){
// Note that this would require to catch CollectionTerminatedException
topDocsCollector = TopFieldCollector.create(sort.sort, topN, true, subSearchContext.trackScores(),
subSearchContext.trackScores(), true);
}
topDocsCollectors.put(bucket, topDocsCollector);
}
final LeafCollector leafCollector;
final int key = leafCollectors.indexOf(bucket);
if (key < 0) {
leafCollector = topDocsCollector.getLeafCollector(ctx);
if (scorer != null) {
leafCollector.setScorer(scorer);
}
leafCollectors.indexInsert(key, bucket, leafCollector);
} else {
leafCollector = leafCollectors.indexGet(key);
}
leafCollector.collect(docId);
}
};
}
@Override
public InternalAggregation buildAggregation(long owningBucketOrdinal) {
TopDocsCollector topDocsCollector = topDocsCollectors.get(owningBucketOrdinal);
final InternalTopHits topHits;
if (topDocsCollector == null) {
topHits = buildEmptyAggregation();
} else {
TopDocs topDocs = topDocsCollector.topDocs();
if (subSearchContext.sort() == null) {
for (RescoreContext ctx : context().rescore()) {
try {
topDocs = ctx.rescorer().rescore(topDocs, context.searcher(), ctx);
} catch (IOException e) {
throw new ElasticsearchException("Rescore TopHits Failed", e);
}
}
}
subSearchContext.queryResult().topDocs(topDocs,
subSearchContext.sort() == null ? null : subSearchContext.sort().formats);
int[] docIdsToLoad = new int[topDocs.scoreDocs.length];
for (int i = 0; i < topDocs.scoreDocs.length; i++) {
docIdsToLoad[i] = topDocs.scoreDocs[i].doc;
}
subSearchContext.docIdsToLoad(docIdsToLoad, 0, docIdsToLoad.length);
fetchPhase.execute(subSearchContext);
FetchSearchResult fetchResult = subSearchContext.fetchResult();
SearchHit[] internalHits = fetchResult.fetchResult().hits().getHits();
for (int i = 0; i < internalHits.length; i++) {
ScoreDoc scoreDoc = topDocs.scoreDocs[i];
SearchHit searchHitFields = internalHits[i];
searchHitFields.shard(subSearchContext.shardTarget());
searchHitFields.score(scoreDoc.score);
if (scoreDoc instanceof FieldDoc) {
FieldDoc fieldDoc = (FieldDoc) scoreDoc;
searchHitFields.sortValues(fieldDoc.fields, subSearchContext.sort().formats);
}
}
topHits = new InternalTopHits(name, subSearchContext.from(), subSearchContext.size(), topDocs, fetchResult.hits(),
pipelineAggregators(), metaData());
}
return topHits;
}
@Override
public InternalTopHits buildEmptyAggregation() {
TopDocs topDocs;
if (subSearchContext.sort() != null) {
topDocs = new TopFieldDocs(0, new FieldDoc[0], subSearchContext.sort().sort.getSort(), Float.NaN);
} else {
topDocs = Lucene.EMPTY_TOP_DOCS;
}
return new InternalTopHits(name, subSearchContext.from(), subSearchContext.size(), topDocs, SearchHits.empty(),
pipelineAggregators(), metaData());
}
@Override
protected void doClose() {
Releasables.close(topDocsCollectors);
}
}