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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.shard;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.index.IndexSettings;
import org.elasticsearch.index.NodeServicesProvider;
import org.elasticsearch.index.cache.IndexCache;
import org.elasticsearch.index.engine.Engine;
import org.elasticsearch.index.engine.EngineConfig;
import org.elasticsearch.index.engine.EngineFactory;
import org.elasticsearch.index.fielddata.IndexFieldDataService;
import org.elasticsearch.index.mapper.MapperService;
import org.elasticsearch.index.merge.MergeStats;
import org.elasticsearch.index.similarity.SimilarityService;
import org.elasticsearch.index.store.Store;
import org.elasticsearch.index.translog.TranslogStats;
import java.io.IOException;
/**
* ShadowIndexShard extends {@link IndexShard} to add file synchronization
* from the primary when a flush happens. It also ensures that a replica being
* promoted to a primary causes the shard to fail, kicking off a re-allocation
* of the primary shard.
*/
public final class ShadowIndexShard extends IndexShard {
public ShadowIndexShard(ShardId shardId, IndexSettings indexSettings, ShardPath path, Store store, IndexCache indexCache, MapperService mapperService, SimilarityService similarityService, IndexFieldDataService indexFieldDataService, @Nullable EngineFactory engineFactory,
IndexEventListener indexEventListener, IndexSearcherWrapper wrapper, NodeServicesProvider provider) throws IOException {
super(shardId, indexSettings, path, store, indexCache, mapperService, similarityService, indexFieldDataService, engineFactory, indexEventListener, wrapper, provider);
}
/**
* In addition to the regular accounting done in
* {@link IndexShard#updateRoutingEntry(org.elasticsearch.cluster.routing.ShardRouting, boolean)},
* if this shadow replica needs to be promoted to a primary, the shard is
* failed in order to allow a new primary to be re-allocated.
*/
@Override
public void updateRoutingEntry(ShardRouting newRouting, boolean persistState) {
if (newRouting.primary() == true) {// becoming a primary
throw new IllegalStateException("can't promote shard to primary");
}
super.updateRoutingEntry(newRouting, persistState);
}
@Override
public MergeStats mergeStats() {
return new MergeStats();
}
@Override
public boolean canIndex() {
return false;
}
@Override
protected Engine newEngine(boolean skipInitialTranslogRecovery, EngineConfig config) {
assert this.shardRouting.primary() == false;
assert skipInitialTranslogRecovery : "can not recover from gateway";
config.setCreate(false); // hardcoded - we always expect an index to be present
return engineFactory.newReadOnlyEngine(config);
}
@Override
public boolean shouldFlush() {
// we don't need to flush since we don't write - all dominated by the primary
return false;
}
public boolean allowsPrimaryPromotion() {
return false;
}
@Override
public TranslogStats translogStats() {
return null; // shadow engine has no translog
}
}
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