Flink Checkpoint

getTriggerExecutions()

• [x] getTriggerExecutions()

  // TODO 检查是否需要触发的所有任务都在运行。如果不是，请中止检查点
    /**
     * Check if all tasks that we need to trigger are running. If not, abort the checkpoint.
     *
     * @return the executions need to be triggered.
     *
     * @throws CheckpointException the exception fails checking
     */
    private Execution[] getTriggerExecutions() throws CheckpointException {
        // TODO 创建一个 Execution 数组
        Execution[] executions = new Execution[tasksToTrigger.length];
        // TODO 遍历 ExecutionVertex
        for (int i = 0; i < tasksToTrigger.length; i++) {
            // TODO 从 ExecutionVertex 中 顶点任务或者当前任务 [该字段不能为空,如果为 null 代表并非所有必须的任务都在运行 ]
            Execution ee = tasksToTrigger[i].getCurrentExecutionAttempt();
            if (ee == null) {
                LOG.info("当前并非所有必需的任务都在运行");
                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);
                // TODO  如果 Task 生命周期 为 RUNNING , 将 ExecutionVertex 填充进 Execution 数组
            } else if (ee.getState() == ExecutionState.RUNNING) {
                executions[i] = ee;
            } else {
                // TODO 不为 null, 状态也不是 Running , 可能是 Task 生命周期中的其他状态  不为 Running 则不能运行
                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);
            }
        }
        return executions;
    }