Thanks Stefan and Aljoscha for your responses.
Stefan - When I mentioned "new window" - I meant the next window being created.
Eg: if the event was in w1 based processing time and the trigger returned FIRE
- then after the window function is computed, what happens to the events in
that window (w1). Are they (elements in w1) propagated to the next processing
time window (w2) ? If not, then what is the difference between FIRE and
FIRE_AND_PURGE and when do we use FIRE vs FIRE_AND PURGE ? Are there any
examples to demonstrated these differences ?
Thanks again for your help.
Mans
On Thursday, November 16, 2017 5:16 AM, Aljoscha Krettek
<aljos...@apache.org> wrote:
Yes, all of this is correct. Sliding windows in fact look like completely
separate windows to the windowing system.
Best,Aljoscha
On 16. Nov 2017, at 10:15, Stefan Richter <s.rich...@data-artisans.com> wrote:
Hi,
I think the effect is pretty straight forward, the elements in a window are not
purged if the trigger is only FIRE and not FIRE_AND_PURGE. Unfortunately, your
question is a bit unclear about what exactly you mean by „new window“: a truly
„new“ window or another triggering of the previous (non-purged) window? In the
first case, it is a new window without the previous elements, in the second
case the window reflects the old contents plus all changes since the last
trigger.
For sliding windows, if I remember correctly, every slide is actually a
different window and elements are just added repeatedly to all windows in which
they belong. So window n+1 should not be affected by whether or not window n
purges or not. Maybe Aljoscha (in CC) can confirm this for us.
Best,Stefan
Am 13.11.2017 um 20:19 schrieb M Singh <mans2si...@yahoo.com>:
Hi Flink Users
I have a few questions about triggers:
If a trigger returns TriggerResult.FIRE from say the onProcessingTime method -
the window computation is triggered but elements are kept in the window. If
there a second invocation of the onProcessingTime method will the elements from
the previous window (which were not purged) a part of the new window
computation along with new events added since the last FIRE event ?
Secondly, how does the FIRE option affect the sliding window computation ?
If there are any other insights/pitfalls while dealing with this, please let me
know.
Thanks
Mans
