/** * Inspect whether {@link ExecutionTask} is the {@link LoopHeadOperator} of the {@link #loopSubplan}. If so, * promote its {@link ExecutionStage} as the loop head. * * @param task to be checked */ public void update(ExecutionTask task) { if (this.headStageCache == null && this.isLoopHead(task)) { this.headStageCache = task.getStage(); } }