Hi Shengkai, Thanks for the answer. The question is do we need to determine if an event in the main stream is late. Let's look at interval join - event is emitted as soon as there is a match between left and right stream. I agree the watermark should pass on versioned table side, because this is the only way to know which version of record should be used. But if we mimics behaviour of interval join then main stream watermark could be skipped.
Regards, Maciek pon., 26 kwi 2021 o 06:14 Shengkai Fang <fskm...@gmail.com> napisał(a): > > Hi, maverick. > > The watermark is used to determine the message is late or early. If we only > use the watermark on versioned table side, we have no means to determine > whether the event in the main stream is ready to emit. > > Best, > Shengkai > > maverick <mac...@brynski.pl> 于2021年4月26日周一 上午2:31写道： >> >> Hi, >> I'm curious why Event Time Temporal Join needs watermarks from both sides to >> perform join. >> >> Shouldn't watermark on versioned table side be enough to perform join ? >> >> >> >> >> >> -- >> Sent from: >> http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/ -- Maciek Bryński
