pvary commented on code in PR #15042: URL: https://github.com/apache/iceberg/pull/15042#discussion_r2721088895
########## flink/v2.1/flink/src/main/java/org/apache/iceberg/flink/maintenance/operator/TriggerManagerOperator.java: ########## @@ -0,0 +1,318 @@ +/* + * 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.List; +import org.apache.flink.annotation.Experimental; +import org.apache.flink.annotation.Internal; +import org.apache.flink.api.common.operators.ProcessingTimeService.ProcessingTimeCallback; +import org.apache.flink.api.common.state.ListState; +import org.apache.flink.api.common.state.ListStateDescriptor; +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.api.common.typeinfo.Types; +import org.apache.flink.metrics.Counter; +import org.apache.flink.metrics.MetricGroup; +import org.apache.flink.runtime.operators.coordination.OperatorEvent; +import org.apache.flink.runtime.operators.coordination.OperatorEventGateway; +import org.apache.flink.runtime.operators.coordination.OperatorEventHandler; +import org.apache.flink.runtime.state.StateInitializationContext; +import org.apache.flink.runtime.state.StateSnapshotContext; +import org.apache.flink.streaming.api.operators.AbstractStreamOperator; +import org.apache.flink.streaming.api.operators.OneInputStreamOperator; +import org.apache.flink.streaming.api.operators.Output; +import org.apache.flink.streaming.api.operators.StreamOperatorParameters; +import org.apache.flink.streaming.api.watermark.Watermark; +import org.apache.flink.streaming.runtime.streamrecord.StreamRecord; +import org.apache.flink.streaming.runtime.tasks.ProcessingTimeService; +import org.apache.iceberg.flink.maintenance.api.Trigger; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; +import org.apache.iceberg.relocated.com.google.common.collect.Iterables; +import org.apache.iceberg.relocated.com.google.common.collect.Lists; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * TriggerManagerOperator sends events to the coordinator to acquire a lock, then waits for the + * response. If the response indicates that the lock has been acquired, it fires a trigger; + * otherwise, it schedules the next attempt. When the job recovers from a failure, tasks from + * different execution paths of the previous run may still be running. Therefore, it first needs to + * send a lock with the maximum timestamp, and then send a recovery trigger. Only after the + * downstream removes this lock can we be sure that all tasks have fully stopped. + */ +@Experimental +@Internal +public class TriggerManagerOperator extends AbstractStreamOperator<Trigger> + implements OneInputStreamOperator<TableChange, Trigger>, + OperatorEventHandler, + ProcessingTimeCallback { + private static final Logger LOG = LoggerFactory.getLogger(TriggerManagerOperator.class); + + private final OperatorEventGateway operatorEventGateway; + private final List<String> maintenanceTaskNames; + private final List<TriggerEvaluator> evaluators; + private transient Long nextEvaluationTime; + private final long minFireDelayMs; + private transient List<TableChange> accumulatedChanges; + private transient ListState<Long> nextEvaluationTimeState; + private transient ListState<TableChange> accumulatedChangesState; + private transient ListState<Long> lastTriggerTimesState; + private transient Counter rateLimiterTriggeredCounter; + private transient Counter concurrentRunThrottledCounter; + private transient Counter nothingToTriggerCounter; + private transient List<Counter> triggerCounters; + private final long lockCheckDelayMs; + private transient List<Long> lastTriggerTimes; + // To keep the task scheduling fair we keep the last triggered task position in memory. + // If we find a task to trigger, then we run it, but after it is finished, we start from the given + // position to prevent "starvation" of the tasks. + // When there is nothing to trigger, we start from the beginning, as the order of the tasks might + // be important (RewriteDataFiles first, and then RewriteManifestFiles later) + private transient int startsFrom = 0; + private transient boolean triggered = false; + private transient Integer taskToStart; + private final String lockId; + private final String tableName; + + public TriggerManagerOperator( + StreamOperatorParameters<Trigger> parameters, + OperatorEventGateway operatorEventGateway, + List<String> maintenanceTaskNames, + List<TriggerEvaluator> evaluators, + long minFireDelayMs, + long lockCheckDelayMs, + String lockId) { + super(parameters); + Preconditions.checkArgument( + maintenanceTaskNames != null && !maintenanceTaskNames.isEmpty(), + "Invalid maintenance task names: null or empty"); + Preconditions.checkArgument( + evaluators != null && !evaluators.isEmpty(), "Invalid evaluators: null or empty"); + Preconditions.checkArgument( + maintenanceTaskNames.size() == evaluators.size(), + "Provide a name and evaluator for all of the maintenance tasks"); + Preconditions.checkArgument(minFireDelayMs > 0, "Minimum fire delay should be at least 1."); + Preconditions.checkArgument( + lockCheckDelayMs > 0, "Minimum lock delay rate should be at least 1 ms."); + + this.operatorEventGateway = operatorEventGateway; + + this.maintenanceTaskNames = maintenanceTaskNames; + this.evaluators = evaluators; + this.minFireDelayMs = minFireDelayMs; + this.lockCheckDelayMs = lockCheckDelayMs; + this.lockId = lockId; + this.tableName = lockId; + } + + @Override + public void open() throws Exception { + super.open(); + MetricGroup mainGroup = TableMaintenanceMetrics.groupFor(getRuntimeContext(), tableName); + this.rateLimiterTriggeredCounter = + mainGroup.counter(TableMaintenanceMetrics.RATE_LIMITER_TRIGGERED); + this.concurrentRunThrottledCounter = + mainGroup.counter(TableMaintenanceMetrics.CONCURRENT_RUN_THROTTLED); + this.nothingToTriggerCounter = mainGroup.counter(TableMaintenanceMetrics.NOTHING_TO_TRIGGER); + this.triggerCounters = Lists.newArrayListWithExpectedSize(maintenanceTaskNames.size()); + for (int taskIndex = 0; taskIndex < maintenanceTaskNames.size(); ++taskIndex) { + triggerCounters.add( + TableMaintenanceMetrics.groupFor( + mainGroup, maintenanceTaskNames.get(taskIndex), taskIndex) + .counter(TableMaintenanceMetrics.TRIGGERED)); + } + } + + @Override + public void initializeState(StateInitializationContext context) throws Exception { + super.initializeState(context); + this.nextEvaluationTimeState = + context + .getOperatorStateStore() + .getListState(new ListStateDescriptor<>("triggerManagerNextTriggerTime", Types.LONG)); + + this.accumulatedChangesState = + context + .getOperatorStateStore() + .getListState( + new ListStateDescriptor<>( + "triggerManagerAccumulatedChange", TypeInformation.of(TableChange.class))); + + this.lastTriggerTimesState = + context + .getOperatorStateStore() + .getListState(new ListStateDescriptor<>("triggerManagerLastTriggerTime", Types.LONG)); + + if (!Iterables.isEmpty(nextEvaluationTimeState.get())) { + nextEvaluationTime = Iterables.getOnlyElement(nextEvaluationTimeState.get()); + } + + long current = getProcessingTimeService().getCurrentProcessingTime(); + + // Initialize from state + if (!Iterables.isEmpty(nextEvaluationTimeState.get())) { + nextEvaluationTime = Iterables.getOnlyElement(nextEvaluationTimeState.get()); + } + + this.accumulatedChanges = Lists.newArrayList(accumulatedChangesState.get()); + this.lastTriggerTimes = Lists.newArrayList(lastTriggerTimesState.get()); + + // Initialize if the state was empty + if (accumulatedChanges.isEmpty()) { + for (int i = 0; i < evaluators.size(); ++i) { + accumulatedChanges.add(TableChange.empty()); + lastTriggerTimes.add(current); + } + } + + if (context.isRestored()) { + // When the job state is restored, there could be ongoing tasks. + // To prevent collision with the new triggers the following is done: + // - add a recovery lock + // - fire a recovery trigger + // This ensures that the tasks of the previous trigger are executed, and the lock is removed + // in the end. The result of the 'tryLock' is ignored as an already existing lock prevents + // collisions as well. + operatorEventGateway.sendEventToCoordinator(new LockAcquiredEvent(lockId, Long.MAX_VALUE)); Review Comment: Let me clarify this point. TableMaintenance is designed to support stateful tasks, meaning that in‑progress tasks may be resumed after a job restart. At the moment, the only stateful MaintenanceTask is DeleteOrphanFiles (via OrphanFilesDetector), which is able to continue and complete its work after a restart. Since file listing can be expensive for large tables, having the ability to resume partially completed work is important to avoid restarting these operations from scratch. In the longer term, it would be good for additional MaintenanceTask implementations to support continuation across restarts as well. -- 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. 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