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ASF GitHub Bot commented on FLINK-7245: --------------------------------------- Github user xccui commented on the issue: https://github.com/apache/flink/pull/4530 Thanks for the comment, @aljoscha. IMO, making the `timeServiceManager` protected indeed will minimise the impact on `AbstractStreamOperator`, while that may introduce duplicated codes in the subclasses. We make some trade-offs here. > Enhance the operators to support holding back watermarks > -------------------------------------------------------- > > Key: FLINK-7245 > URL: https://issues.apache.org/jira/browse/FLINK-7245 > Project: Flink > Issue Type: New Feature > Components: DataStream API > Reporter: Xingcan Cui > Assignee: Xingcan Cui > > Currently the watermarks are applied and emitted by the > {{AbstractStreamOperator}} instantly. > {code:java} > public void processWatermark(Watermark mark) throws Exception { > if (timeServiceManager != null) { > timeServiceManager.advanceWatermark(mark); > } > output.emitWatermark(mark); > } > {code} > Some calculation results (with timestamp fields) triggered by these > watermarks (e.g., join or aggregate results) may be regarded as delayed by > the downstream operators since their timestamps must be less than or equal to > the corresponding triggers. > This issue aims to add another "working mode", which supports holding back > watermarks, to current operators. These watermarks should be blocked and > stored by the operators until all the corresponding new generated results are > emitted. -- This message was sent by Atlassian JIRA (v6.4.14#64029)