ifndef-SleePy commented on a change in pull request #10332: [FLINK-13905][checkpointing] Separate checkpoint triggering into several asynchronous stages URL: https://github.com/apache/flink/pull/10332#discussion_r368263483
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/checkpoint/CheckpointCoordinator.java ########## @@ -485,76 +481,152 @@ public boolean isShutdown() { CheckpointProperties props, @Nullable String externalSavepointLocation, boolean isPeriodic, - boolean advanceToEndOfTime) throws CheckpointException { + boolean advanceToEndOfTime) { if (advanceToEndOfTime && !(props.isSynchronous() && props.isSavepoint())) { - throw new IllegalArgumentException("Only synchronous savepoints are allowed to advance the watermark to MAX."); + return FutureUtils.completedExceptionally(new IllegalArgumentException( + "Only synchronous savepoints are allowed to advance the watermark to MAX.")); } - // make some eager pre-checks + final CompletableFuture<CompletedCheckpoint> onCompletionPromise = + new CompletableFuture<>(); synchronized (lock) { - preCheckBeforeTriggeringCheckpoint(isPeriodic, props.forceCheckpoint()); - } - - // check if all tasks that we need to trigger are running. - // if not, abort the checkpoint - Execution[] executions = new Execution[tasksToTrigger.length]; - for (int i = 0; i < tasksToTrigger.length; i++) { - Execution ee = tasksToTrigger[i].getCurrentExecutionAttempt(); - if (ee == null) { - LOG.info("Checkpoint triggering task {} of job {} is not being executed at the moment. Aborting checkpoint.", - tasksToTrigger[i].getTaskNameWithSubtaskIndex(), - job); - throw new CheckpointException(CheckpointFailureReason.NOT_ALL_REQUIRED_TASKS_RUNNING); - } else if (ee.getState() == ExecutionState.RUNNING) { - executions[i] = ee; - } else { - LOG.info("Checkpoint triggering task {} of job {} is not in state {} but {} instead. Aborting checkpoint.", - tasksToTrigger[i].getTaskNameWithSubtaskIndex(), - job, - ExecutionState.RUNNING, - ee.getState()); - throw new CheckpointException(CheckpointFailureReason.NOT_ALL_REQUIRED_TASKS_RUNNING); + if (isTriggering || !triggerRequestQueue.isEmpty()) { + // we can't trigger checkpoint directly if there is a trigger request being processed + // or queued + triggerRequestQueue.add(new CheckpointTriggerRequest( + timestamp, + props, + externalSavepointLocation, + isPeriodic, + advanceToEndOfTime, + onCompletionPromise)); + return onCompletionPromise; } } + startTriggeringCheckpoint( + timestamp, + props, + externalSavepointLocation, + isPeriodic, + advanceToEndOfTime, + onCompletionPromise); + return onCompletionPromise; + } - // next, check if all tasks that need to acknowledge the checkpoint are running. - // if not, abort the checkpoint - Map<ExecutionAttemptID, ExecutionVertex> ackTasks = new HashMap<>(tasksToWaitFor.length); + private void startTriggeringCheckpoint( + long timestamp, + CheckpointProperties props, + @Nullable String externalSavepointLocation, + boolean isPeriodic, + boolean advanceToEndOfTime, + CompletableFuture<CompletedCheckpoint> onCompletionPromise) { - for (ExecutionVertex ev : tasksToWaitFor) { - Execution ee = ev.getCurrentExecutionAttempt(); - if (ee != null) { - ackTasks.put(ee.getAttemptId(), ev); - } else { - LOG.info("Checkpoint acknowledging task {} of job {} is not being executed at the moment. Aborting checkpoint.", - ev.getTaskNameWithSubtaskIndex(), - job); - throw new CheckpointException(CheckpointFailureReason.NOT_ALL_REQUIRED_TASKS_RUNNING); + try { + // make some eager pre-checks + synchronized (lock) { + preCheckBeforeTriggeringCheckpoint(isPeriodic, props.forceCheckpoint()); } - } - // we will actually trigger this checkpoint! + final Execution[] executions = getTriggerExecutions(); + final Map<ExecutionAttemptID, ExecutionVertex> ackTasks = getAckTasks(); + + // we will actually trigger this checkpoint! + Preconditions.checkState(!isTriggering); + isTriggering = true; + + final CompletableFuture<PendingCheckpoint> pendingCheckpointCompletableFuture = + initializeCheckpoint(props, externalSavepointLocation) + .thenApplyAsync( + (checkpointIdAndStorageLocation) -> createPendingCheckpoint( + timestamp, + props, + ackTasks, + isPeriodic, + checkpointIdAndStorageLocation.checkpointId, + checkpointIdAndStorageLocation.checkpointStorageLocation, + onCompletionPromise), + timer); + + pendingCheckpointCompletableFuture + .thenCompose(this::snapshotMasterState) + .whenCompleteAsync( + (ignored, throwable) -> { + final PendingCheckpoint checkpoint = + FutureUtils.getWithoutException(pendingCheckpointCompletableFuture); + + if (throwable == null && checkpoint != null && !checkpoint.isDiscarded()) { + // no exception, no discarding, everything is OK + snapshotTaskState( + timestamp, + checkpoint.getCheckpointId(), + checkpoint.getCheckpointStorageLocation(), + props, + executions, + advanceToEndOfTime); + onTriggerSuccess(); + } else { + // the initialization might not be finished yet + if (checkpoint == null) { + onTriggerFailure(onCompletionPromise, throwable); + } else { + onTriggerFailure(checkpoint, throwable); + } + } + }, + timer); + } catch (Throwable throwable) { + onTriggerFailure(onCompletionPromise, throwable); Review comment: Yes, `startTriggeringCheckpoint` must be executed in timer thread. 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