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Shuo Cheng edited comment on FLINK-5601 at 11/21/18 3:16 AM: ------------------------------------------------------------- Hi, JiaYi, You say that the watermark restored is the lowest in the union state, but actually, I find that you use the highest watermark in the code, is that what you mean here? was (Author: icshuo): Hi, JiaYi, You say that the watermark restored is the lowest in the union state, but actually, I find that you use the highest watermark in the code? > Window operator does not checkpoint watermarks > ---------------------------------------------- > > Key: FLINK-5601 > URL: https://issues.apache.org/jira/browse/FLINK-5601 > Project: Flink > Issue Type: Improvement > Components: State Backends, Checkpointing > Affects Versions: 1.5.0, 1.6.0, 1.7.0 > Reporter: Ufuk Celebi > Assignee: Jiayi Liao > Priority: Critical > Labels: pull-request-available > Fix For: 1.8.0 > > > During release testing [~stefanrichte...@gmail.com] and I noticed that > watermarks are not checkpointed in the window operator. > This can lead to non determinism when restoring checkpoints. I was running an > adjusted {{SessionWindowITCase}} via Kafka for testing migration and > rescaling and ran into failures, because the data generator required > determinisitic behaviour. > What happened was that on restore it could happen that late elements were not > dropped, because the watermarks needed to be re-established after restore > first. > [~aljoscha] Do you know whether there is a special reason for explicitly not > checkpointing watermarks? -- This message was sent by Atlassian JIRA (v7.6.3#76005)