Trigger Firing for Late Window Elements

[Scott Kidder]

I'm using event-time windows of 1 hour that have an allowed lateness of
several hours. This supports the processing of access logs that can be
delayed by several hours. The windows aggregate data over the 1 hour period
and write to a database sink. Pretty straightforward.

Will the event-time trigger lead to the window trigger firing for every
single late element? Suppose thousands of late elements arrive
simultaneously; I'd like to avoid having that lead to thousands of database
updates in a short period of time. Ideally, I could batch up the late
window changes and have it trigger when the window is finally closed or
some processing-time duration passes (e.g. once per minute).

For reference, here's what the aggregate window definition looks like with
Flink 1.5.3:

        chunkSource.keyBy(record -> record.getRecord().getEnvironmentId())
                .timeWindow(Time.hours(1))
                .allowedLateness(Time.hours(3))
                .aggregate(new EnvironmentAggregateWatchTimeFunction())
                .uid("env-watchtime-stats")
                .name("Env Watch-Time Stats")
                .addSink(new EnvironmentWatchTimeDBSink());


Thank you,

--
Scott Kidder