org.elasticsearch.action.search.FetchSearchPhase Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of elasticsearch Show documentation
Show all versions of elasticsearch Show documentation
Elasticsearch subproject :server
/*
* 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.action.search;
import com.carrotsearch.hppc.IntArrayList;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.message.ParameterizedMessage;
import org.apache.logging.log4j.util.Supplier;
import org.apache.lucene.search.ScoreDoc;
import org.elasticsearch.action.ActionRunnable;
import org.elasticsearch.action.OriginalIndices;
import org.elasticsearch.common.util.concurrent.AtomicArray;
import org.elasticsearch.search.SearchPhaseResult;
import org.elasticsearch.search.SearchShardTarget;
import org.elasticsearch.search.fetch.FetchSearchResult;
import org.elasticsearch.search.fetch.ShardFetchSearchRequest;
import org.elasticsearch.search.internal.InternalSearchResponse;
import org.elasticsearch.search.query.QuerySearchResult;
import org.elasticsearch.transport.Transport;
import java.io.IOException;
import java.util.List;
import java.util.function.BiFunction;
/**
* This search phase merges the query results from the previous phase together and calculates the topN hits for this search.
* Then it reaches out to all relevant shards to fetch the topN hits.
*/
final class FetchSearchPhase extends SearchPhase {
private final AtomicArray fetchResults;
private final SearchPhaseController searchPhaseController;
private final AtomicArray queryResults;
private final BiFunction nextPhaseFactory;
private final SearchPhaseContext context;
private final Logger logger;
private final InitialSearchPhase.SearchPhaseResults resultConsumer;
FetchSearchPhase(InitialSearchPhase.SearchPhaseResults resultConsumer,
SearchPhaseController searchPhaseController,
SearchPhaseContext context) {
this(resultConsumer, searchPhaseController, context,
(response, scrollId) -> new ExpandSearchPhase(context, response, // collapse only happens if the request has inner hits
(finalResponse) -> sendResponsePhase(finalResponse, scrollId, context)));
}
FetchSearchPhase(InitialSearchPhase.SearchPhaseResults resultConsumer,
SearchPhaseController searchPhaseController,
SearchPhaseContext context, BiFunction nextPhaseFactory) {
super("fetch");
if (context.getNumShards() != resultConsumer.getNumShards()) {
throw new IllegalStateException("number of shards must match the length of the query results but doesn't:"
+ context.getNumShards() + "!=" + resultConsumer.getNumShards());
}
this.fetchResults = new AtomicArray<>(resultConsumer.getNumShards());
this.searchPhaseController = searchPhaseController;
this.queryResults = resultConsumer.getAtomicArray();
this.nextPhaseFactory = nextPhaseFactory;
this.context = context;
this.logger = context.getLogger();
this.resultConsumer = resultConsumer;
}
@Override
public void run() throws IOException {
context.execute(new ActionRunnable(context) {
@Override
public void doRun() throws IOException {
// we do the heavy lifting in this inner run method where we reduce aggs etc. that's why we fork this phase
// off immediately instead of forking when we send back the response to the user since there we only need
// to merge together the fetched results which is a linear operation.
innerRun();
}
@Override
public void onFailure(Exception e) {
context.onPhaseFailure(FetchSearchPhase.this, "", e);
}
});
}
private void innerRun() throws IOException {
final int numShards = context.getNumShards();
final boolean isScrollSearch = context.getRequest().scroll() != null;
List phaseResults = queryResults.asList();
String scrollId = isScrollSearch ? TransportSearchHelper.buildScrollId(queryResults) : null;
final SearchPhaseController.ReducedQueryPhase reducedQueryPhase = resultConsumer.reduce();
final boolean queryAndFetchOptimization = queryResults.length() == 1;
final Runnable finishPhase = ()
-> moveToNextPhase(searchPhaseController, scrollId, reducedQueryPhase, queryAndFetchOptimization ?
queryResults : fetchResults);
if (queryAndFetchOptimization) {
assert phaseResults.isEmpty() || phaseResults.get(0).fetchResult() != null : "phaseResults empty [" + phaseResults.isEmpty()
+ "], single result: " + phaseResults.get(0).fetchResult();
// query AND fetch optimization
finishPhase.run();
} else {
final IntArrayList[] docIdsToLoad = searchPhaseController.fillDocIdsToLoad(numShards, reducedQueryPhase.scoreDocs);
if (reducedQueryPhase.scoreDocs.length == 0) { // no docs to fetch -- sidestep everything and return
phaseResults.stream()
.map(SearchPhaseResult::queryResult)
.forEach(this::releaseIrrelevantSearchContext); // we have to release contexts here to free up resources
finishPhase.run();
} else {
final ScoreDoc[] lastEmittedDocPerShard = isScrollSearch ?
searchPhaseController.getLastEmittedDocPerShard(reducedQueryPhase, numShards)
: null;
final CountedCollector counter = new CountedCollector<>(r -> fetchResults.set(r.getShardIndex(), r),
docIdsToLoad.length, // we count down every shard in the result no matter if we got any results or not
finishPhase, context);
for (int i = 0; i < docIdsToLoad.length; i++) {
IntArrayList entry = docIdsToLoad[i];
SearchPhaseResult queryResult = queryResults.get(i);
if (entry == null) { // no results for this shard ID
if (queryResult != null) {
// if we got some hits from this shard we have to release the context there
// we do this as we go since it will free up resources and passing on the request on the
// transport layer is cheap.
releaseIrrelevantSearchContext(queryResult.queryResult());
}
// in any case we count down this result since we don't talk to this shard anymore
counter.countDown();
} else {
SearchShardTarget searchShardTarget = queryResult.getSearchShardTarget();
Transport.Connection connection = context.getConnection(searchShardTarget.getClusterAlias(),
searchShardTarget.getNodeId());
ShardFetchSearchRequest fetchSearchRequest = createFetchRequest(queryResult.queryResult().getRequestId(), i, entry,
lastEmittedDocPerShard, searchShardTarget.getOriginalIndices());
executeFetch(i, searchShardTarget, counter, fetchSearchRequest, queryResult.queryResult(),
connection);
}
}
}
}
}
protected ShardFetchSearchRequest createFetchRequest(long queryId, int index, IntArrayList entry,
ScoreDoc[] lastEmittedDocPerShard, OriginalIndices originalIndices) {
final ScoreDoc lastEmittedDoc = (lastEmittedDocPerShard != null) ? lastEmittedDocPerShard[index] : null;
return new ShardFetchSearchRequest(originalIndices, queryId, entry, lastEmittedDoc);
}
private void executeFetch(final int shardIndex, final SearchShardTarget shardTarget,
final CountedCollector counter,
final ShardFetchSearchRequest fetchSearchRequest, final QuerySearchResult querySearchResult,
final Transport.Connection connection) {
context.getSearchTransport().sendExecuteFetch(connection, fetchSearchRequest, context.getTask(),
new SearchActionListener(shardTarget, shardIndex) {
@Override
public void innerOnResponse(FetchSearchResult result) {
counter.onResult(result);
}
@Override
public void onFailure(Exception e) {
try {
if (logger.isDebugEnabled()) {
logger.debug((Supplier) () -> new ParameterizedMessage("[{}] Failed to execute fetch phase",
fetchSearchRequest.id()), e);
}
counter.onFailure(shardIndex, shardTarget, e);
} finally {
// the search context might not be cleared on the node where the fetch was executed for example
// because the action was rejected by the thread pool. in this case we need to send a dedicated
// request to clear the search context.
releaseIrrelevantSearchContext(querySearchResult);
}
}
});
}
/**
* Releases shard targets that are not used in the docsIdsToLoad.
*/
private void releaseIrrelevantSearchContext(QuerySearchResult queryResult) {
// we only release search context that we did not fetch from if we are not scrolling
// and if it has at lease one hit that didn't make it to the global topDocs
if (context.getRequest().scroll() == null && queryResult.hasSearchContext()) {
try {
SearchShardTarget searchShardTarget = queryResult.getSearchShardTarget();
Transport.Connection connection = context.getConnection(searchShardTarget.getClusterAlias(), searchShardTarget.getNodeId());
context.sendReleaseSearchContext(queryResult.getRequestId(), connection, searchShardTarget.getOriginalIndices());
} catch (Exception e) {
context.getLogger().trace("failed to release context", e);
}
}
}
private void moveToNextPhase(SearchPhaseController searchPhaseController,
String scrollId, SearchPhaseController.ReducedQueryPhase reducedQueryPhase,
AtomicArray fetchResultsArr) {
final InternalSearchResponse internalResponse = searchPhaseController.merge(context.getRequest().scroll() != null,
reducedQueryPhase, fetchResultsArr.asList(), fetchResultsArr::get);
context.executeNextPhase(this, nextPhaseFactory.apply(internalResponse, scrollId));
}
private static SearchPhase sendResponsePhase(InternalSearchResponse response, String scrollId, SearchPhaseContext context) {
return new SearchPhase("response") {
@Override
public void run() throws IOException {
context.onResponse(context.buildSearchResponse(response, scrollId));
}
};
}
}