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Merged
merged 10 commits into from
Jun 18, 2018
Merged

Avoid sending duplicate remote failed shard requests #31313

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99562c0
TEST: getCapturedRequestsAndClear should be atomic
dnhatn Jun 14, 2018
251d44c
Avoid sending duplicate remote failed shard requests
dnhatn Jun 13, 2018
71a2db4
Merge branch 'master' into cache-remote-shards-failed
dnhatn Jun 14, 2018
6a704c7
Simplify report
dnhatn Jun 14, 2018
7601a13
Remove identity map
dnhatn Jun 14, 2018
19baf31
Revert "TEST: getCapturedRequestsAndClear should be atomic"
dnhatn Jun 15, 2018
dcdaba7
Merge branch 'master' into cache-remote-shards-failed
dnhatn Jun 15, 2018
a102531
Address Yannick’s comments
dnhatn Jun 18, 2018
56da910
Merge branch 'master' into cache-remote-shards-failed
dnhatn Jun 18, 2018
496a6bd
Randomize primary term
dnhatn Jun 18, 2018
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125 changes: 122 additions & 3 deletions server/src/main/java/org/elasticsearch/cluster/action/shard/ShardStateAction.java
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Original file line number Diff line number Diff line change
Expand Up @@ -25,10 +25,10 @@
import org.elasticsearch.ExceptionsHelper;
import org.elasticsearch.Version;
import org.elasticsearch.cluster.ClusterChangedEvent;
import org.elasticsearch.cluster.ClusterStateTaskExecutor;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.ClusterStateObserver;
import org.elasticsearch.cluster.ClusterStateTaskConfig;
import org.elasticsearch.cluster.ClusterStateTaskExecutor;
import org.elasticsearch.cluster.ClusterStateTaskListener;
import org.elasticsearch.cluster.MasterNodeChangePredicate;
import org.elasticsearch.cluster.NotMasterException;
Expand All @@ -48,6 +48,7 @@
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.unit.TimeValue;
import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
import org.elasticsearch.discovery.Discovery;
import org.elasticsearch.index.shard.ShardId;
import org.elasticsearch.node.NodeClosedException;
Expand All @@ -68,7 +69,9 @@
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Objects;
import java.util.Set;
import java.util.concurrent.ConcurrentMap;
import java.util.function.Predicate;

public class ShardStateAction extends AbstractComponent {
Expand All @@ -80,6 +83,10 @@ public class ShardStateAction extends AbstractComponent {
private final ClusterService clusterService;
private final ThreadPool threadPool;

// a list of shards that failed during replication
// we keep track of these shards in order to avoid sending duplicate failed shard requests for a single failing shard.
private final ConcurrentMap<FailedShardEntry, CompositeListener> remoteFailedShardsCache = ConcurrentCollections.newConcurrentMap();

@Inject
public ShardStateAction(Settings settings, ClusterService clusterService, TransportService transportService,
AllocationService allocationService, RoutingService routingService, ThreadPool threadPool) {
Expand Down Expand Up @@ -146,8 +153,35 @@ private static boolean isMasterChannelException(TransportException exp) {
*/
public void remoteShardFailed(final ShardId shardId, String allocationId, long primaryTerm, boolean markAsStale, final String message, @Nullable final Exception failure, Listener listener) {
assert primaryTerm > 0L : "primary term should be strictly positive";
FailedShardEntry shardEntry = new FailedShardEntry(shardId, allocationId, primaryTerm, message, failure, markAsStale);
sendShardAction(SHARD_FAILED_ACTION_NAME, clusterService.state(), shardEntry, listener);
final FailedShardEntry shardEntry = new FailedShardEntry(shardId, allocationId, primaryTerm, message, failure, markAsStale);
final CompositeListener compositeListener = new CompositeListener(listener);
final CompositeListener existingListener = remoteFailedShardsCache.putIfAbsent(shardEntry, compositeListener);
if (existingListener == null) {
sendShardAction(SHARD_FAILED_ACTION_NAME, clusterService.state(), shardEntry, new Listener() {
@Override
public void onSuccess() {
try {
compositeListener.onSuccess();
} finally {
remoteFailedShardsCache.remove(shardEntry);
}
}
@Override
public void onFailure(Exception e) {
try {
compositeListener.onFailure(e);
} finally {
remoteFailedShardsCache.remove(shardEntry);
}
}
});
} else {
existingListener.addListener(listener);
}
}

int remoteShardFailedCacheSize() {
return remoteFailedShardsCache.size();
}

/**
Expand Down Expand Up @@ -414,6 +448,23 @@ public String toString() {
components.add("markAsStale [" + markAsStale + "]");
return String.join(", ", components);
}

@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
FailedShardEntry that = (FailedShardEntry) o;
// Exclude message and exception from equals and hashCode
return Objects.equals(this.shardId, that.shardId) &&
Objects.equals(this.allocationId, that.allocationId) &&
primaryTerm == that.primaryTerm &&
markAsStale == that.markAsStale;
}

@Override
public int hashCode() {
return Objects.hash(shardId, allocationId, primaryTerm, markAsStale);
}
}

public void shardStarted(final ShardRouting shardRouting, final String message, Listener listener) {
Expand Down Expand Up @@ -585,6 +636,74 @@ default void onFailure(final Exception e) {

}

/**
* A composite listener that allows registering multiple listeners dynamically.
*/
static final class CompositeListener implements Listener {
private boolean isNotified = false;
private Exception failure = null;
private final List<Listener> listeners = new ArrayList<>();

CompositeListener(Listener listener) {
listeners.add(listener);
}

void addListener(Listener listener) {
final boolean ready;
synchronized (this) {
ready = this.isNotified;
if (ready == false) {
listeners.add(listener);
}
}
if (ready) {
if (failure != null) {
listener.onFailure(failure);
} else {
listener.onSuccess();
}
}
}

private void onCompleted(Exception failure) {
final List<Listener> listeners;
synchronized (this) {
this.failure = failure;
listeners = this.listeners;
this.isNotified = true;
}
Exception firstException = null;
for (Listener listener : listeners) {
try {
if (failure != null) {
listener.onFailure(failure);
} else {
listener.onSuccess();
}
} catch (Exception innerEx) {
if (firstException == null) {
firstException = innerEx;
} else {
firstException.addSuppressed(innerEx);
}
}
}
if (firstException != null) {
throw new ElasticsearchException("failed to notify listener", firstException);
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where is this exception going to end up?

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It's an interesting question. It will be reported as unhandled by the transport threads. The same thing should happen for the current implementation.

}
}

@Override
public void onSuccess() {
onCompleted(null);
}

@Override
public void onFailure(Exception failure) {
onCompleted(failure);
}
}

public static class NoLongerPrimaryShardException extends ElasticsearchException {

public NoLongerPrimaryShardException(ShardId shardId, String msg) {
Expand Down
32 changes: 20 additions & 12 deletions ...java/org/elasticsearch/cluster/action/shard/ShardFailedClusterStateTaskExecutorTests.java
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Original file line number Diff line number Diff line change
Expand Up @@ -22,11 +22,11 @@
import com.carrotsearch.hppc.cursors.ObjectCursor;
import org.apache.lucene.index.CorruptIndexException;
import org.elasticsearch.Version;
import org.elasticsearch.cluster.action.shard.ShardStateAction.FailedShardEntry;
import org.elasticsearch.cluster.ClusterName;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.ClusterStateTaskExecutor;
import org.elasticsearch.cluster.ESAllocationTestCase;
import org.elasticsearch.cluster.action.shard.ShardStateAction.FailedShardEntry;
import org.elasticsearch.cluster.metadata.IndexMetaData;
import org.elasticsearch.cluster.metadata.MetaData;
import org.elasticsearch.cluster.node.DiscoveryNodes;
Expand All @@ -52,10 +52,10 @@
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.IdentityHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

Expand Down Expand Up @@ -131,9 +131,14 @@ ClusterState applyFailedShards(ClusterState currentState, List<FailedShard> fail
tasks.addAll(failingTasks);
tasks.addAll(nonExistentTasks);
ClusterStateTaskExecutor.ClusterTasksResult<FailedShardEntry> result = failingExecutor.execute(currentState, tasks);
Map<FailedShardEntry, ClusterStateTaskExecutor.TaskResult> taskResultMap =
failingTasks.stream().collect(Collectors.toMap(Function.identity(), task -> ClusterStateTaskExecutor.TaskResult.failure(new RuntimeException("simulated applyFailedShards failure"))));
taskResultMap.putAll(nonExistentTasks.stream().collect(Collectors.toMap(Function.identity(), task -> ClusterStateTaskExecutor.TaskResult.success())));
Map<FailedShardEntry, ClusterStateTaskExecutor.TaskResult> taskResultMap = new IdentityHashMap<>();
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what's the reason for turning this into a identity map?

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Previously we did not override FailedShardEntry, but now we do. I used an identity map because we verify that the size of the resultMap equals the number of tasks.

I replaced these maps with a list. I think it's clearer now.

for (FailedShardEntry failingTask : failingTasks) {
taskResultMap.put(failingTask,
ClusterStateTaskExecutor.TaskResult.failure(new RuntimeException("simulated applyFailedShards failure")));
}
for (FailedShardEntry nonExistentTask : nonExistentTasks) {
taskResultMap.put(nonExistentTask, ClusterStateTaskExecutor.TaskResult.success());
}
assertTaskResults(taskResultMap, result, currentState, false);
}

Expand All @@ -147,12 +152,13 @@ public void testIllegalShardFailureRequests() throws Exception {
tasks.add(new FailedShardEntry(failingTask.shardId, failingTask.allocationId,
randomIntBetween(1, (int) primaryTerm - 1), failingTask.message, failingTask.failure, randomBoolean()));
}
Map<FailedShardEntry, ClusterStateTaskExecutor.TaskResult> taskResultMap =
tasks.stream().collect(Collectors.toMap(
Function.identity(),
task -> ClusterStateTaskExecutor.TaskResult.failure(new ShardStateAction.NoLongerPrimaryShardException(task.shardId,
Map<FailedShardEntry, ClusterStateTaskExecutor.TaskResult> taskResultMap = new IdentityHashMap<>();
for (FailedShardEntry task : tasks) {
taskResultMap.put(task,
ClusterStateTaskExecutor.TaskResult.failure(new ShardStateAction.NoLongerPrimaryShardException(task.shardId,
"primary term [" + task.primaryTerm + "] did not match current primary term [" +
currentState.metaData().index(task.shardId.getIndex()).primaryTerm(task.shardId.id()) + "]"))));
currentState.metaData().index(task.shardId.getIndex()).primaryTerm(task.shardId.id()) + "]")));
}
ClusterStateTaskExecutor.ClusterTasksResult<FailedShardEntry> result = executor.execute(currentState, tasks);
assertTaskResults(taskResultMap, result, currentState, false);
}
Expand Down Expand Up @@ -251,8 +257,10 @@ private static void assertTasksSuccessful(
ClusterState clusterState,
boolean clusterStateChanged
) {
Map<ShardStateAction.FailedShardEntry, ClusterStateTaskExecutor.TaskResult> taskResultMap =
tasks.stream().collect(Collectors.toMap(Function.identity(), task -> ClusterStateTaskExecutor.TaskResult.success()));
Map<ShardStateAction.FailedShardEntry, ClusterStateTaskExecutor.TaskResult> taskResultMap = new IdentityHashMap<>();
for (FailedShardEntry task : tasks) {
taskResultMap.put(task, ClusterStateTaskExecutor.TaskResult.success());
}
assertTaskResults(taskResultMap, result, clusterState, clusterStateChanged);
}

Expand Down
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