Hi, Piotr Thanks for replying. I asked this because such a pattern might imply memory oversubscription. For example, I tuned down the memory of one app from heap 2.63GB to 367MB and the job still runs fine: before: https://drive.google.com/file/d/1o8k9Vv3yb5gXITi4GvmlXMteQcRfmOhr/view?usp=sharing
after: https://drive.google.com/file/d/1wNTHBT8aSJaAmL1rVY8jUkdp-G5znnMN/view?usp=sharing What's the best practice for tuning Flink job memory? 1. What’s a good start point users should try first? 2. How to make progress? e.g. flink application Foo currently encountered error OOM: java heap space. Where to move next? simply bump up taskmananger.memory? or just increase heap? 3. What’s the final state? Job running fine and ensuring XYZ headroom in each memory component? Best Lu On Tue, Apr 6, 2021 at 12:26 AM Piotr Nowojski <pnowoj...@apache.org> wrote: > Hi, > > this should be posted on the user mailing list not the dev. > > Apart from that, this looks like normal/standard behaviour of JVM, and has > very little to do with Flink. Garbage Collector (GC) is kicking in when > memory usage is approaching some threshold: > https://www.google.com/search?q=jvm+heap+memory+usage&tbm=isch > > Piotrek > > > pon., 5 kwi 2021 o 22:54 Lu Niu <qqib...@gmail.com> napisał(a): > > > Hi, > > > > we need to update our email system then :) . Here are the links: > > > > > > > https://drive.google.com/file/d/1lZ5_P8_NqsN1JeLzutGj4DxkyWJN75mR/view?usp=sharing > > > > > > > https://drive.google.com/file/d/1J6c6rQJwtDp1moAGlvQyLQXTqcuG4HjL/view?usp=sharing > > > > > > > https://drive.google.com/file/d/1-R2KzsABC471AEjkF5qTm5O3V47cpbBV/view?usp=sharing > > > > All are DataStream job. > > > > Best > > Lu > > > > On Sun, Apr 4, 2021 at 9:17 PM Yun Gao <yungao...@aliyun.com> wrote: > > > > > > > > Hi Lu, > > > > > > The image seems not be able to shown due to the mail server limitation, > > > could you upload it somewhere and paste the link here ? > > > > > > Logically, I think zigzag usually due to there are some small object > get > > > created and eliminated soon in the heap. Are you running a SQL job or a > > > DataStream job ? > > > > > > Best, > > > Yun > > > > > > ------------------------------------------------------------------ > > > Sender:Lu Niu<qqib...@gmail.com> > > > Date:2021/04/05 12:06:24 > > > Recipient:d...@flink.apache.org<d...@flink.apache.org> > > > Theme:Zigzag shape in TM JVM used memory > > > > > > Hi, Flink dev > > > > > > We observed that the TM JVM used memory metric shows zigzag shape among > > > lots of our applications, although these applications are quite > different > > > in business logic. The upper bound is close to the max heap size. Is > this > > > expected in flink application? Or does flink internally > > > aggressively pre-allocate memory? > > > > > > app1 > > > [image: Screen Shot 2021-04-04 at 8.46.45 PM.png] > > > app2 > > > [image: Screen Shot 2021-04-04 at 8.45.35 PM.png] > > > app3 > > > [image: Screen Shot 2021-04-04 at 8.43.53 PM.png] > > > > > > Best > > > Lu > > > > > > > > >
