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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.index.engine;
import org.apache.logging.log4j.Logger;
import org.apache.lucene.index.ConcurrentMergeScheduler;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.MergePolicy;
import org.apache.lucene.index.MergeScheduler;
import org.apache.lucene.index.OneMergeHelper;
import org.elasticsearch.common.logging.Loggers;
import org.elasticsearch.common.metrics.CounterMetric;
import org.elasticsearch.common.metrics.MeanMetric;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.unit.ByteSizeValue;
import org.elasticsearch.common.unit.TimeValue;
import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
import org.elasticsearch.common.util.concurrent.EsExecutors;
import org.elasticsearch.index.IndexSettings;
import org.elasticsearch.index.MergeSchedulerConfig;
import org.elasticsearch.index.merge.MergeStats;
import org.elasticsearch.index.merge.OnGoingMerge;
import org.elasticsearch.index.shard.ShardId;
import java.io.IOException;
import java.util.Collections;
import java.util.Locale;
import java.util.Set;
/**
* An extension to the {@link ConcurrentMergeScheduler} that provides tracking on merge times, total
* and current merges.
*/
class ElasticsearchConcurrentMergeScheduler extends ConcurrentMergeScheduler {
protected final Logger logger;
private final Settings indexSettings;
private final ShardId shardId;
private final MeanMetric totalMerges = new MeanMetric();
private final CounterMetric totalMergesNumDocs = new CounterMetric();
private final CounterMetric totalMergesSizeInBytes = new CounterMetric();
private final CounterMetric currentMerges = new CounterMetric();
private final CounterMetric currentMergesNumDocs = new CounterMetric();
private final CounterMetric currentMergesSizeInBytes = new CounterMetric();
private final CounterMetric totalMergeStoppedTime = new CounterMetric();
private final CounterMetric totalMergeThrottledTime = new CounterMetric();
private final Set<OnGoingMerge> onGoingMerges = ConcurrentCollections.newConcurrentSet();
private final Set<OnGoingMerge> readOnlyOnGoingMerges = Collections.unmodifiableSet(onGoingMerges);
private final MergeSchedulerConfig config;
ElasticsearchConcurrentMergeScheduler(ShardId shardId, IndexSettings indexSettings) {
this.config = indexSettings.getMergeSchedulerConfig();
this.shardId = shardId;
this.indexSettings = indexSettings.getSettings();
this.logger = Loggers.getLogger(getClass(), this.indexSettings, shardId);
refreshConfig();
}
public Set<OnGoingMerge> onGoingMerges() {
return readOnlyOnGoingMerges;
}
@Override
protected void doMerge(IndexWriter writer, MergePolicy.OneMerge merge) throws IOException {
int totalNumDocs = merge.totalNumDocs();
long totalSizeInBytes = merge.totalBytesSize();
long timeNS = System.nanoTime();
currentMerges.inc();
currentMergesNumDocs.inc(totalNumDocs);
currentMergesSizeInBytes.inc(totalSizeInBytes);
OnGoingMerge onGoingMerge = new OnGoingMerge(merge);
onGoingMerges.add(onGoingMerge);
if (logger.isTraceEnabled()) {
logger.trace("merge [{}] starting..., merging [{}] segments, [{}] docs, [{}] size, into [{}] estimated_size", OneMergeHelper.getSegmentName(merge), merge.segments.size(), totalNumDocs, new ByteSizeValue(totalSizeInBytes), new ByteSizeValue(merge.estimatedMergeBytes));
}
try {
beforeMerge(onGoingMerge);
super.doMerge(writer, merge);
} finally {
long tookMS = TimeValue.nsecToMSec(System.nanoTime() - timeNS);
onGoingMerges.remove(onGoingMerge);
afterMerge(onGoingMerge);
currentMerges.dec();
currentMergesNumDocs.dec(totalNumDocs);
currentMergesSizeInBytes.dec(totalSizeInBytes);
totalMergesNumDocs.inc(totalNumDocs);
totalMergesSizeInBytes.inc(totalSizeInBytes);
totalMerges.inc(tookMS);
long stoppedMS = TimeValue.nsecToMSec(
merge.getMergeProgress().getPauseTimes().get(MergePolicy.OneMergeProgress.PauseReason.STOPPED)
);
long throttledMS = TimeValue.nsecToMSec(
merge.getMergeProgress().getPauseTimes().get(MergePolicy.OneMergeProgress.PauseReason.PAUSED)
);
final Thread thread = Thread.currentThread();
long totalBytesWritten = OneMergeHelper.getTotalBytesWritten(thread, merge);
double mbPerSec = OneMergeHelper.getMbPerSec(thread, merge);
totalMergeStoppedTime.inc(stoppedMS);
totalMergeThrottledTime.inc(throttledMS);
String message = String.format(Locale.ROOT,
"merge segment [%s] done: took [%s], [%,.1f MB], [%,d docs], [%s stopped], [%s throttled], [%,.1f MB written], [%,.1f MB/sec throttle]",
OneMergeHelper.getSegmentName(merge),
TimeValue.timeValueMillis(tookMS),
totalSizeInBytes/1024f/1024f,
totalNumDocs,
TimeValue.timeValueMillis(stoppedMS),
TimeValue.timeValueMillis(throttledMS),
totalBytesWritten/1024f/1024f,
mbPerSec);
if (tookMS > 20000) { // if more than 20 seconds, DEBUG log it
logger.debug("{}", message);
} else if (logger.isTraceEnabled()) {
logger.trace("{}", message);
}
}
}
/**
* A callback allowing for custom logic before an actual merge starts.
*/
protected void beforeMerge(OnGoingMerge merge) {}
/**
* A callback allowing for custom logic before an actual merge starts.
*/
protected void afterMerge(OnGoingMerge merge) {}
@Override
public MergeScheduler clone() {
// Lucene IW makes a clone internally but since we hold on to this instance
// the clone will just be the identity.
return this;
}
@Override
protected boolean maybeStall(IndexWriter writer) {
// Don't stall here, because we do our own index throttling (in InternalEngine.IndexThrottle) when merges can't keep up
return true;
}
@Override
protected MergeThread getMergeThread(IndexWriter writer, MergePolicy.OneMerge merge) throws IOException {
MergeThread thread = super.getMergeThread(writer, merge);
thread.setName(EsExecutors.threadName(indexSettings, "[" + shardId.getIndexName() + "][" + shardId.id() + "]: " + thread.getName()));
return thread;
}
MergeStats stats() {
final MergeStats mergeStats = new MergeStats();
mergeStats.add(totalMerges.count(), totalMerges.sum(), totalMergesNumDocs.count(), totalMergesSizeInBytes.count(),
currentMerges.count(), currentMergesNumDocs.count(), currentMergesSizeInBytes.count(),
totalMergeStoppedTime.count(),
totalMergeThrottledTime.count(),
config.isAutoThrottle() ? getIORateLimitMBPerSec() : Double.POSITIVE_INFINITY);
return mergeStats;
}
void refreshConfig() {
if (this.getMaxMergeCount() != config.getMaxMergeCount() || this.getMaxThreadCount() != config.getMaxThreadCount()) {
this.setMaxMergesAndThreads(config.getMaxMergeCount(), config.getMaxThreadCount());
}
boolean isEnabled = getIORateLimitMBPerSec() != Double.POSITIVE_INFINITY;
if (config.isAutoThrottle() && isEnabled == false) {
enableAutoIOThrottle();
} else if (config.isAutoThrottle() == false && isEnabled) {
disableAutoIOThrottle();
}
}
}