Hi Vinay, These methods are useful when using your trigger with SessionWindows. When using session windows, the state of a window and that of the corresponding trigger has to be merged with that of other windows.
These methods do exactly that: the canMerge() says if the trigger can be used with Session Windows, and if yes, the onMerge() includes the logic of what to do with the trigger state when a window merging happens. As an example you can check out the CountTrigger. I hope this answers your question. Cheers, Kostas > On Oct 4, 2016, at 6:10 PM, vinay patil <vinay18.pa...@gmail.com> wrote: > > Hi Kostas, > > Yes you are right , I am always doing FIRE_AND_PURGE , if we don't do this > and only use FIRE , the window function will get the elements in incremental > fashion (1, 2,3..so on) > I had observed this while testing. > > Can you please explain me the importance of canMerge and onMerge functions in > trigger, from the javadocs I got it on a high level, but not able to > understand it correctly (so I am not using these functions for now in Custom > Trigger). > > Regards, > Vinay Patil > > On Tue, Oct 4, 2016 at 10:51 AM, Kostas Kloudas [via Apache Flink User > Mailing List archive.] <[hidden email] > <x-msg://14/user/SendEmail.jtp?type=node&node=9331&i=0>> wrote: > Hi Vinay, > > By setting the allowed_lateness to LongMax you are ok. > Sorry I forgot that this was the default value. > > Just a note (although you have it right in your code), in this case > you should always FIRE_AND_PURGE and not just FIRE. In other > case your state will keep growing as it is never garbage collected. > > Cheers, > Kostas > > >> On Oct 4, 2016, at 5:42 PM, vinay patil <[hidden email] >> <http://user/SendEmail.jtp?type=node&node=9329&i=0>> wrote: >> >> Long.MAX_VALUE > > > > If you reply to this email, your message will be added to the discussion > below: > http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Regarding-Late-Elements-tp9284p9329.html > > <http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Regarding-Late-Elements-tp9284p9329.html> > To start a new topic under Apache Flink User Mailing List archive., email > [hidden email] <x-msg://14/user/SendEmail.jtp?type=node&node=9331&i=1> > To unsubscribe from Apache Flink User Mailing List archive., click here > <applewebdata://6844F060-0841-49DA-811F-B7AE5E851424>. > NAML > <http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml> > > View this message in context: Re: Regarding Late Elements > <http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Regarding-Late-Elements-tp9284p9331.html> > Sent from the Apache Flink User Mailing List archive. mailing list archive > <http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/> at > Nabble.com.
