Hi Till

Super, understood! I will also read the website with the link that you provided 
me.

Thanks  and have a nice eve.

best

s

________________________________
From: Till Rohrmann <trohrm...@apache.org>
Sent: 02 December 2020 17:44
To: Simone Cavallarin <cavalla...@hotmail.com>
Cc: user <user@flink.apache.org>
Subject: Re: Process windows not firing - > Can it be a Watermak issue?

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<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fci.apache.org%2Fprojects%2Fflink%2Fflink-docs-stable%2Fdev%2Fevent_time.html&data=04%7C01%7C%7C4d4822a42cf84a4ac54908d896e9fddb%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637425279012441040%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=9J8R9AuOuBztrnh1zvkA46rAGWKw%2BgKSFSCgo%2FTPv4w%3D&reserved=0>

Cheers,
Till

On Wed, Dec 2, 2020 at 6:17 PM Simone Cavallarin 
<cavalla...@hotmail.com<mailto:cavalla...@hotmail.com>> 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 <da...@alpinegizmo.com<mailto:da...@alpinegizmo.com>>
Sent: 02 December 2020 16:01
To: Simone Cavallarin <cavalla...@hotmail.com<mailto:cavalla...@hotmail.com>>
Cc: user <user@flink.apache.org<mailto:user@flink.apache.org>>
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 <trohrm...@apache.org<mailto:trohrm...@apache.org>>
Sent: 02 December 2020 15:46
To: Simone Cavallarin <cavalla...@hotmail.com<mailto:cavalla...@hotmail.com>>
Cc: user <user@flink.apache.org<mailto:user@flink.apache.org>>
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


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