flinksql 視窗提前觸發

場景：一天的視窗，想每分鐘或其他時間點觸發一次

insert into sliding_window_local_pay_day
select userid,
  TUMBLE_START (ptime, INTERVAL '1' DAY) as window_start,
  TUMBLE_END (ptime, INTERVAL '1' DAY) as window_end,
  COUNT (1) as pay_num
from
  flink_kafka_join_pay
group by TUMBLE (ptime, INTERVAL '1' DAY), userid;
           

1. 兩個參數：每分鐘觸發一次

table.exec.emit.early-fire.enabled: 'true'
table.exec.emit.early-fire.delay: 60s 
           

2. 源碼中觸發也就是生成 Trigger

生成Trigger的邏輯是視窗聚合的key的第一條資料時間點+N個Interval，也就是不同的key 觸發的時間點不一樣

/**
     * Creates a trigger that fires by a certain interval after reception of the first element.
     *
     * @param time the certain interval
     */
    public static <W extends Window> AfterFirstElementPeriodic<W> every(Duration time) {
        return new AfterFirstElementPeriodic<>(time.toMillis());
    }
           

3. 觸發的效果，不同的userid，觸發的時間點是不同的