Hi Simone, You need to set this option because otherwise Flink will not generate the Watermarks. If you don't need watermarks (e.g. when using ProcessingTime), then the system needs to send fewer records over the wire. That's basically how Flink has been developed [1].
With Flink 1.12 this option no longer needs to be set because it is activated by default. [1] https://ci.apache.org/projects/flink/flink-docs-stable/dev/event_time.html Cheers, Till On Wed, Dec 2, 2020 at 6:17 PM Simone Cavallarin <[email protected]> wrote: > Hi Till and David, > > First at all thanks for the quick reply, really appreciated! > > Drilling down to the issue: > > > 1. *No session is closing because there isn't a sufficiently long gap > in the test data *-> It was the first thing that I thought, before > asking I run a test checking the gap on my data an using a super small > interval of 10 millis. The problem was not this. > 2. *The test runs to completion before the periodic watermark > generator has generated any watermarks.* -> The data is flowing for > hours and i can see everything debugging the flow, every event was with > all information, I'm mapping my stream and use the stream it self to > compute the gap, so I play a while with it. > 3. *Which version of Flink are you using?* - > 1.11.2 > 4. *Have you enabled event time support via > > StreamExecutionEnvironment.setStreamTimeCharacteristic(TimeCharacteristic.EventTime)? > -* > BINGO! this was the issue, as soon as I added this line on the > code it started to work!! 🙂 (It would be nice to understand what this > magic line is doing!) > 5. *The fact that assigner has no field to display simply means that > it contains no fields which is normal for lambda functions-*> Thanks I > didn't know that. noted! > > > Why > StreamExecutionEnvironment.setStreamTimeCharacteristic(TimeCharacteristic.EventTime) > is so important? > > Thanks > > s > > > > ------------------------------ > *From:* David Anderson <[email protected]> > *Sent:* 02 December 2020 16:01 > *To:* Simone Cavallarin <[email protected]> > *Cc:* user <[email protected]> > *Subject:* Re: Process windows not firing - > Can it be a Watermak issue? > > In cases like this one, one of the following tends to be the explanation: > > - No session is closing because there isn't a sufficiently long gap in the > test data. > - The test runs to completion before the periodic watermark generator has > generated any watermarks. > > David > > *From:* Till Rohrmann <[email protected]> > *Sent:* 02 December 2020 15:46 > *To:* Simone Cavallarin <[email protected]> > *Cc:* user <[email protected]> > *Subject:* Re: Process windows not firing - > Can it be a Watermak issue? > > Hi Simone, > > Which version of Flink are you using? Have you enabled event time support > via > StreamExecutionEnvironment.setStreamTimeCharacteristic(TimeCharacteristic.EventTime)? > Are you sure that the topic you are consuming contains data? Maybe you can > share the whole job with example data with us so that we can take a look at > it as a whole. > > The fact that assigner has no field to display simply means that it > contains no fields which is normal for lambda functions. > > Cheers, > Till > > >
