mxm commented on code in PR #15151: URL: https://github.com/apache/iceberg/pull/15151#discussion_r2803050167
########## flink/v2.1/flink/src/main/java/org/apache/iceberg/flink/maintenance/operator/TriggerManagerCoordinator.java: ########## @@ -0,0 +1,108 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF 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.apache.iceberg.flink.maintenance.operator; + +import java.util.Locale; +import java.util.concurrent.CompletableFuture; +import org.apache.flink.annotation.Experimental; +import org.apache.flink.annotation.Internal; +import org.apache.flink.runtime.operators.coordination.OperatorEvent; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +@Experimental +@Internal +public class TriggerManagerCoordinator extends BaseCoordinator { + + private static final Logger LOG = LoggerFactory.getLogger(TriggerManagerCoordinator.class); + + public TriggerManagerCoordinator(String operatorName, Context context) { + super(operatorName, context); + LOG.info("Created TriggerManagerCoordinator: {}", operatorName); + } + + @Override + public void handleEventFromOperator(int subtask, int attemptNumber, OperatorEvent event) { + runInCoordinatorThread( + () -> { + LOG.debug( + "Handling event from subtask {} (#{}) of {}: {}", + subtask, + attemptNumber, + operatorName(), + event); + if (event instanceof LockRegisterEvent) { + registerLock((LockRegisterEvent) event); + } else { + throw new IllegalArgumentException( + "Invalid operator event type: " + event.getClass().getCanonicalName()); + } + }, + String.format( + Locale.ROOT, + "handling operator event %s from subtask %d (#%d)", + event.getClass(), + subtask, + attemptNumber)); + } + + @SuppressWarnings("FutureReturnValueIgnored") + private void registerLock(LockRegisterEvent lockRegisterEvent) { + LOCK_RELEASE_CONSUMERS.put( + lockRegisterEvent.lockId(), + lock -> { + LOG.info( + "Send release event for lock id {}, timestamp: {} to Operator {}", + lock.lockId(), + lock.timestamp(), + operatorName()); + subtaskGateways().getSubtaskGateway(0).sendEvent(lock); + }); + + PENDING_RELEASE_EVENTS.forEach(this::handleReleaseLock); + PENDING_RELEASE_EVENTS.clear(); Review Comment: That would work fine if we were using the same coordinator, but we have two coordinators. Unless we ensure that only one of the two coordinators processes events at the same time, the above assumption doesn't hold. Consider this scenario: 1. TriggerManagerOperator sends LockRegisterEvent 2. Maintenance tasks running 3. Maintenance task finished 4. LockRemoverOperator sends LockReleaseEvent 5. TriggerManagerCoordinator processes LockRegisterEvent 6. LockRemoverCoordinator processes LockReleaseEvent This results in a deadlock because we only acquire the lock in TriggerManagerOperator during initializeState(). -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
