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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.merge.scheduler;
import org.apache.lucene.index.MergePolicy;
import org.apache.lucene.index.MergeScheduler;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.index.merge.EnableMergeScheduler;
import org.elasticsearch.index.merge.MergeStats;
import org.elasticsearch.index.merge.OnGoingMerge;
import org.elasticsearch.index.settings.IndexSettings;
import org.elasticsearch.index.shard.AbstractIndexShardComponent;
import org.elasticsearch.index.shard.IndexShardComponent;
import org.elasticsearch.index.shard.ShardId;
import org.elasticsearch.threadpool.ThreadPool;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArrayList;
/**
*
*/
public abstract class MergeSchedulerProvider extends AbstractIndexShardComponent implements IndexShardComponent {
public static final String FORCE_ASYNC_MERGE = "index.merge.force_async_merge";
public static interface FailureListener {
void onFailedMerge(MergePolicy.MergeException e);
}
/**
* Listener for events before/after single merges. Called on the merge thread.
*/
public static interface Listener {
/**
* A callback before a merge is going to execute. Note, any logic here will block the merge
* till its done.
*/
void beforeMerge(OnGoingMerge merge);
/**
* A callback after a merge is going to execute. Note, any logic here will block the merge
* thread.
*/
void afterMerge(OnGoingMerge merge);
}
private final ThreadPool threadPool;
private final CopyOnWriteArrayList<FailureListener> failureListeners = new CopyOnWriteArrayList<>();
private final CopyOnWriteArrayList<Listener> listeners = new CopyOnWriteArrayList<>();
private final boolean notifyOnMergeFailure;
protected MergeSchedulerProvider(ShardId shardId, @IndexSettings Settings indexSettings, ThreadPool threadPool) {
super(shardId, indexSettings);
this.threadPool = threadPool;
this.notifyOnMergeFailure = componentSettings.getAsBoolean("notify_on_failure", true);
}
public void addFailureListener(FailureListener listener) {
failureListeners.add(listener);
}
public void addListener(Listener listener) {
listeners.add(listener);
}
public void removeListener(Listener listener) {
listeners.remove(listener);
}
protected void failedMerge(final MergePolicy.MergeException e) {
if (!notifyOnMergeFailure) {
return;
}
for (final FailureListener failureListener : failureListeners) {
threadPool.generic().execute(new Runnable() {
@Override
public void run() {
failureListener.onFailedMerge(e);
}
});
}
}
protected void beforeMerge(OnGoingMerge merge) {
for (Listener listener : listeners) {
listener.beforeMerge(merge);
}
}
protected void afterMerge(OnGoingMerge merge) {
for (Listener listener : listeners) {
listener.afterMerge(merge);
}
}
public final MergeScheduler newMergeScheduler() {
MergeScheduler scheduler = buildMergeScheduler();
// an internal settings, that would allow us to disable this behavior if really needed
if (indexSettings.getAsBoolean(FORCE_ASYNC_MERGE, true)) {
scheduler = new EnableMergeScheduler(scheduler);
}
return scheduler;
}
/** Maximum number of allowed running merges before index throttling kicks in. */
public abstract int getMaxMerges();
protected abstract MergeScheduler buildMergeScheduler();
public abstract MergeStats stats();
public abstract Set<OnGoingMerge> onGoingMerges();
public abstract void close();
}