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Piotr Nowojski commented on FLINK-18934: ---------------------------------------- Note to anyone who will be fixing this issue. In the {{MultipleInputStreamTaskTest#testWatermarkAndStreamStatusForwarding}} (implemented as part of FLINK-18907 ) there is a workaround of this bug, that needs to be removed when this bug is fixed. > Idle stream does not advance watermark in connected stream > ---------------------------------------------------------- > > Key: FLINK-18934 > URL: https://issues.apache.org/jira/browse/FLINK-18934 > Project: Flink > Issue Type: Bug > Components: API / DataStream > Affects Versions: 1.11.1 > Reporter: Truong Duc Kien > Priority: Critical > Fix For: 1.12.0, 1.11.3 > > > Per Flink documents, when a stream is idle, it will allow watermarks of > downstream operator to advance. However, when I connect an active data stream > with an idle data stream, the output watermark of the CoProcessOperator does > not increase. > Here's a small test that reproduces the problem. > https://github.com/kien-truong/flink-idleness-testing -- This message was sent by Atlassian Jira (v8.3.4#803005)