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Elasticsearch subproject :server
/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.index.engine;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexCommit;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.LeafReader;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.index.SegmentReader;
import org.apache.lucene.store.Directory;
import org.elasticsearch.common.lucene.Lucene;
import org.elasticsearch.core.Nullable;
import org.elasticsearch.index.seqno.SeqNoStats;
import org.elasticsearch.index.seqno.SequenceNumbers;
import org.elasticsearch.index.shard.DocsStats;
import org.elasticsearch.index.store.Store;
import org.elasticsearch.index.translog.Translog;
import org.elasticsearch.index.translog.TranslogConfig;
import org.elasticsearch.index.translog.TranslogDeletionPolicy;
import org.elasticsearch.index.translog.TranslogStats;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.util.List;
import java.util.Map;
import java.util.function.Function;
/**
* NoOpEngine is an engine implementation that does nothing but the bare minimum
* required in order to have an engine. All attempts to do something (search,
* index, get), throw {@link UnsupportedOperationException}. However, NoOpEngine
* allows to trim any existing translog files through the usage of the
* {{@link #trimUnreferencedTranslogFiles()}} method.
*/
public final class NoOpEngine extends ReadOnlyEngine {
private final SegmentsStats segmentsStats;
private final DocsStats docsStats;
public NoOpEngine(EngineConfig config) {
this(
config,
config.isPromotableToPrimary() ? null : new TranslogStats(0, 0, 0, 0, 0),
config.isPromotableToPrimary()
? null
: new SeqNoStats(
config.getGlobalCheckpointSupplier().getAsLong(),
config.getGlobalCheckpointSupplier().getAsLong(),
config.getGlobalCheckpointSupplier().getAsLong()
)
);
}
public NoOpEngine(EngineConfig config, @Nullable TranslogStats translogStats, SeqNoStats seqNoStats) {
super(config, seqNoStats, translogStats, true, Function.identity(), true, true);
this.segmentsStats = new SegmentsStats();
Directory directory = store.directory();
try (DirectoryReader reader = openDirectory(directory)) {
for (LeafReaderContext ctx : reader.getContext().leaves()) {
SegmentReader segmentReader = Lucene.segmentReader(ctx.reader());
fillSegmentStats(segmentReader, true, segmentsStats);
}
this.docsStats = docsStats(reader);
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
@Override
protected DirectoryReader open(final IndexCommit commit) throws IOException {
final Directory directory = commit.getDirectory();
final List indexCommits = DirectoryReader.listCommits(directory);
final IndexCommit indexCommit = indexCommits.get(indexCommits.size() - 1);
return new DirectoryReader(directory, new LeafReader[0], null) {
@Override
protected DirectoryReader doOpenIfChanged() {
return null;
}
@Override
protected DirectoryReader doOpenIfChanged(IndexCommit commit) {
return null;
}
@Override
protected DirectoryReader doOpenIfChanged(IndexWriter writer, boolean applyAllDeletes) {
return null;
}
@Override
public long getVersion() {
return 0;
}
@Override
public boolean isCurrent() {
return true;
}
@Override
public IndexCommit getIndexCommit() {
return indexCommit;
}
@Override
protected void doClose() {}
@Override
public CacheHelper getReaderCacheHelper() {
return null;
}
};
}
@Override
public SegmentsStats segmentsStats(boolean includeSegmentFileSizes, boolean includeUnloadedSegments) {
if (includeUnloadedSegments) {
final SegmentsStats stats = new SegmentsStats();
stats.add(this.segmentsStats);
if (includeSegmentFileSizes == false) {
stats.clearFiles();
}
return stats;
} else {
return super.segmentsStats(includeSegmentFileSizes, includeUnloadedSegments);
}
}
@Override
public DocsStats docStats() {
return docsStats;
}
/**
* This implementation will trim existing translog files using a {@link TranslogDeletionPolicy}
* that retains nothing but the last translog generation from safe commit.
*/
@Override
public void trimUnreferencedTranslogFiles() {
final Store store = this.engineConfig.getStore();
store.incRef();
try (var ignored = acquireEnsureOpenRef()) {
final List commits = DirectoryReader.listCommits(store.directory());
if (commits.size() == 1 && translogStats.getTranslogSizeInBytes() > translogStats.getUncommittedSizeInBytes()) {
final Map commitUserData = getLastCommittedSegmentInfos().getUserData();
final String translogUuid = commitUserData.get(Translog.TRANSLOG_UUID_KEY);
if (translogUuid == null) {
throw new IllegalStateException("commit doesn't contain translog unique id");
}
final TranslogConfig translogConfig = engineConfig.getTranslogConfig();
final long localCheckpoint = Long.parseLong(commitUserData.get(SequenceNumbers.LOCAL_CHECKPOINT_KEY));
final TranslogDeletionPolicy translogDeletionPolicy = new TranslogDeletionPolicy();
translogDeletionPolicy.setLocalCheckpointOfSafeCommit(localCheckpoint);
try (
Translog translog = new Translog(
translogConfig,
translogUuid,
translogDeletionPolicy,
engineConfig.getGlobalCheckpointSupplier(),
engineConfig.getPrimaryTermSupplier(),
seqNo -> {}
)
) {
translog.trimUnreferencedReaders();
// refresh the translog stats
this.translogStats = translog.stats();
assert translog.currentFileGeneration() == translog.getMinFileGeneration()
: "translog was not trimmed "
+ " current gen "
+ translog.currentFileGeneration()
+ " != min gen "
+ translog.getMinFileGeneration();
}
}
} catch (final Exception e) {
try {
failEngine("translog trimming failed", e);
} catch (Exception inner) {
e.addSuppressed(inner);
}
throw new EngineException(shardId, "failed to trim translog", e);
} finally {
store.decRef();
}
}
}