Hi Caizhi,
Thanks for responding. What i mean specifically is that if I do
something like this
env
.addSource(events)
.keyBy(....)
.window(TumblingEventTimeWindows.of(Time.seconds(1)))
.trigger(new EmptyTrigger())
.process(new MyProcessFunction())
.addSink(...)
Where EmptyTrigger is defined as,
public class EmptyTrigger extends Trigger<MyElement, TimeWindow> {
@Override
public TriggerResult onElement(MyElement element, long timestamp,
TimeWindow window, TriggerContext ctx) throws Exception {
return TriggerResult.CONTINUE;
}
@Override
public TriggerResult onProcessingTime(long time, TimeWindow window,
TriggerContext ctx) throws Exception {
System.out.println("Processing Time: " + time);
return TriggerResult.FIRE;
}
@Override
public TriggerResult onEventTime(long time, TimeWindow window,
TriggerContext ctx) throws Exception {
System.out.println("Event Time: " + time);
return TriggerResult.FIRE;
}
@Override
public void clear(TimeWindow window, TriggerContext ctx) throws
Exception {
}
}
I will see the onEventTime method above fire every second. However I have
not registered any timers in the above EmptyTrigger. My question becomes
where are those timers coming from? The documentation states,
"By specifying a trigger using trigger() you are overwriting the default
trigger of a WindowAssigner."
This is the puzzling part to me about the above statement.
Thanks,
Aeden
On Tue, Aug 31, 2021 at 7:58 PM Caizhi Weng <[email protected]> wrote:
> Hi!
>
> I don't quite understand this problem. But if you look into
> WindowedStream#trigger you'll find that the trigger
> of WindowOperatorBuilder will change when you call that method, and thus
> the default trigger will be overwritten by calling WindowedStream#trigger.
>
> Aeden Jameson <[email protected]> 于2021年9月1日周三 上午12:32写道：
>
>> Flink Version: 1.13.2
>>
>> In the section on Default Triggers of Window Assigners the documentation
>> States
>>
>> By specifying a trigger using trigger() you are overwriting the default
>> trigger of a WindowAssigner. For example, if you specify a CountTrigger
>> for TumblingEventTimeWindows you will no longer get window firings
>> based on the progress of time but only by count.
>>
>> While I find the example given to be true because the CountTrigger
>> doesn't FIRE in OnEventTime the timers of the default trigger are still
>> being registered. Is that accurate? So when writing a custom trigger
>> against the default trigger of a window one still needs to handle those
>> timers and decide to fire them or not. It may be just me, but the
>> documentation gives the impression that nothing would happen if one
>> specifies a custom trigger with .trigger(...). I'm I understanding what's
>> going on in the code around timers, default and custom triggers correctly?
>> If so it seems one solution to this would be to inherit from said
>> WindowAssign and override the getDefaultTrigger method.
>>
>>
>> --
>> Thanks,
>> Aeden
>>
>>
>>
