Add a soft limit on the number of shards that can be queried in a single search request. #17396

This commit adds the new `action.search.shard_count.limit` setting which
configures the maximum number of shards that can be queried in a single search
request. It has a default value of 1000.
This commit is contained in:
Adrien Grand 2016-03-30 09:58:42 +02:00
parent e25ccb91ae
commit d7179cafcc
5 changed files with 98 additions and 1 deletions

View File

@ -107,7 +107,16 @@ abstract class AbstractSearchAsyncAction<FirstResult extends SearchPhaseResult>
request.indices());
shardsIts = clusterService.operationRouting().searchShards(clusterState, concreteIndices, routingMap, request.preference());
expectedSuccessfulOps = shardsIts.size();
final int shardCount = shardsIts.size();
final long shardCountLimit = clusterService.getClusterSettings().get(TransportSearchAction.SHARD_COUNT_LIMIT_SETTING);
if (shardCount > shardCountLimit) {
throw new IllegalArgumentException("Trying to query " + shardCount + " shards, which is over the limit of "
+ shardCountLimit + ". This limit exists because querying many shards at the same time can make the "
+ "job of the coordinating node very CPU and/or memory intensive. It is usually a better idea to "
+ "have a smaller number of larger shards. Update [" + TransportSearchAction.SHARD_COUNT_LIMIT_SETTING.getKey()
+ "] to a greater value if you really want to query that many shards at the same time.");
}
expectedSuccessfulOps = shardCount;
// we need to add 1 for non active partition, since we count it in the total!
expectedTotalOps = shardsIts.totalSizeWith1ForEmpty();

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@ -26,6 +26,8 @@ import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
import org.elasticsearch.cluster.service.ClusterService;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.settings.Setting;
import org.elasticsearch.common.settings.Setting.Property;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.index.IndexNotFoundException;
import org.elasticsearch.indices.IndexClosedException;
@ -45,6 +47,10 @@ import static org.elasticsearch.action.search.SearchType.QUERY_THEN_FETCH;
*/
public class TransportSearchAction extends HandledTransportAction<SearchRequest, SearchResponse> {
/** The maximum number of shards for a single search request. */
public static final Setting<Long> SHARD_COUNT_LIMIT_SETTING = Setting.longSetting(
"action.search.shard_count.limit", 1000L, 1L, Property.Dynamic, Property.NodeScope);
private final ClusterService clusterService;
private final SearchTransportService searchTransportService;
private final SearchPhaseController searchPhaseController;

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@ -19,6 +19,7 @@
package org.elasticsearch.common.settings;
import org.elasticsearch.action.admin.indices.close.TransportCloseIndexAction;
import org.elasticsearch.action.search.TransportSearchAction;
import org.elasticsearch.action.support.AutoCreateIndex;
import org.elasticsearch.action.support.DestructiveOperations;
import org.elasticsearch.action.support.master.TransportMasterNodeReadAction;
@ -258,6 +259,7 @@ public final class ClusterSettings extends AbstractScopedSettings {
ClusterService.CLUSTER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING,
SearchService.DEFAULT_SEARCH_TIMEOUT_SETTING,
ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING,
TransportSearchAction.SHARD_COUNT_LIMIT_SETTING,
TransportService.TRACE_LOG_EXCLUDE_SETTING,
TransportService.TRACE_LOG_INCLUDE_SETTING,
TransportCloseIndexAction.CLUSTER_INDICES_CLOSE_ENABLE_SETTING,

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@ -0,0 +1,73 @@
/*
* 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 org.elasticsearch.cluster.metadata.IndexMetaData;
import org.elasticsearch.test.ESIntegTestCase;
import java.util.Collections;
import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
import static org.hamcrest.Matchers.containsString;
public class TransportSearchIT extends ESIntegTestCase {
public void testShardCountLimit() throws Exception {
try {
final int numPrimaries1 = randomIntBetween(2, 10);
final int numPrimaries2 = randomIntBetween(1, 10);
assertAcked(prepareCreate("test1")
.setSettings(IndexMetaData.SETTING_NUMBER_OF_SHARDS, numPrimaries1));
assertAcked(prepareCreate("test2")
.setSettings(IndexMetaData.SETTING_NUMBER_OF_SHARDS, numPrimaries2));
ensureYellow("test1", "test2");
// no exception
client().prepareSearch("test1").get();
assertAcked(client().admin().cluster().prepareUpdateSettings()
.setTransientSettings(Collections.singletonMap(
TransportSearchAction.SHARD_COUNT_LIMIT_SETTING.getKey(), numPrimaries1 - 1)));
IllegalArgumentException e = expectThrows(IllegalArgumentException.class,
() -> client().prepareSearch("test1").get());
assertThat(e.getMessage(), containsString("Trying to query " + numPrimaries1
+ " shards, which is over the limit of " + (numPrimaries1 - 1)));
assertAcked(client().admin().cluster().prepareUpdateSettings()
.setTransientSettings(Collections.singletonMap(
TransportSearchAction.SHARD_COUNT_LIMIT_SETTING.getKey(), numPrimaries1)));
// no exception
client().prepareSearch("test1").get();
e = expectThrows(IllegalArgumentException.class,
() -> client().prepareSearch("test1", "test2").get());
assertThat(e.getMessage(), containsString("Trying to query " + (numPrimaries1 + numPrimaries2)
+ " shards, which is over the limit of " + numPrimaries1));
} finally {
assertAcked(client().admin().cluster().prepareUpdateSettings()
.setTransientSettings(Collections.singletonMap(
TransportSearchAction.SHARD_COUNT_LIMIT_SETTING.getKey(), null)));
}
}
}

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@ -49,3 +49,10 @@ Or even search across all indices and all types:
--------------------------------------------------
$ curl -XGET 'http://localhost:9200/_search?q=tag:wow'
--------------------------------------------------
By default elasticsearch rejects search requests that would query more than
1000 shards. The reason is that such large numbers of shards make the job of
the coordinating node very CPU and memory intensive. It is usually a better
idea to organize data in such a way that there are fewer larger shards. In
case you would like to bypass this limit, which is discouraged, you can update
the `action.search.shard_count.limit` cluster setting to a greater value.