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Aljoscha Krettek commented on FLINK-10050: ------------------------------------------ I think {{DataStream.join()}} and {{DataStream.coGroup()}} are a bit of a dead end because they don't allow getting any information about what window the result is in, or other meta information about the window that you would get from a {{ProcessWindowFunction}}. I'm interested if you have a use case for this, where you don't need to know what window your result is in. > Support 'allowedLateness' in CoGroupedStreams > --------------------------------------------- > > Key: FLINK-10050 > URL: https://issues.apache.org/jira/browse/FLINK-10050 > Project: Flink > Issue Type: Improvement > Components: Streaming > Affects Versions: 1.5.1, 1.6.0 > Reporter: eugen yushin > Priority: Major > Labels: ready-to-commit, windows > > WindowedStream has a support of 'allowedLateness' feature, while > CoGroupedStreams are not. At the mean time, WindowedStream is an inner part > of CoGroupedStreams and all main functionality (like evictor/trigger/...) is > simply delegated to WindowedStream. > There's no chance to operate with late arriving data from previous steps in > cogroups (and joins). Consider the following flow: > a. read data from source1 -> aggregate data with allowed lateness > b. read data from source2 -> aggregate data with allowed lateness > c. cogroup/join streams a and b, and compare aggregated values > Step c doesn't accept any late data from steps a/b due to lack of > `allowedLateness` API call in CoGroupedStreams.java. > Scope: add method `WithWindow.allowedLateness` to Java API > (flink-streaming-java) and extend scala API (flink-streaming-scala). -- This message was sent by Atlassian JIRA (v7.6.3#76005)