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Ori Popowski edited comment on FLINK-16929 at 4/2/20, 9:32 AM: --------------------------------------------------------------- Hi, I've made some progress. I've forgot to mention that we "split" the stream and write to two sinks. I've deployed a version without the "split" and it seems that the problem went away. Is it possible that this is what causes it? (By split I mean that we take the initial KeyedStream and one branch is a session window, and the other is a side output without any windowing) was (Author: oripwk): Hi, I've made some progress. I've forgot to mention that we "split" the stream and write to two sinks. I've deployed a version without the "split" and it seems that the problem went away. Is it possible that this is what causes it? > Session Window produces sessions randomly > ----------------------------------------- > > Key: FLINK-16929 > URL: https://issues.apache.org/jira/browse/FLINK-16929 > Project: Flink > Issue Type: Bug > Affects Versions: 1.9.1 > Reporter: Ori Popowski > Priority: Major > Attachments: image-2020-04-01-19-56-00-239.png, > image-2020-04-01-19-56-27-720.png > > > We have a Flink job which keyBys session ID (sId), and uses a session window > with 30 minutes gap: > {code:java} > inputStream > .keyBy(keySelector) > .window(EventTimeSessionWindows.withGap(Time.minutes(30))) > .allowedLateness(Time.seconds(0L)) > {code} > This Flink job reads from Kinesis stream. > Lately (I suspect after upgrading from 1.5.4 to 1.9.1) we get too many > sessions, with gaps of several seconds (instead of 30 minutes). > We have no idea why it's happening and suspect a Flink bug or a state backend > bug (we use RocksDB). > I haven't found any indication in the logs except for some read throughput > warnings which were resolved by a backoff. > Attached is a table of derived sessions, and then the raw events > *Sessions* > !image-2020-04-01-19-56-00-239.png|width=753,height=406! > > *Events* > > !image-2020-04-01-19-56-27-720.png|width=312,height=383! > > > > -- This message was sent by Atlassian Jira (v8.3.4#803005)