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Alexander Shoshin commented on FLINK-3133: ------------------------------------------ [~mxm], could you give more details about this issue please? It is not clear for me. First about print(). I can see that {{DataStream}} has already have such method. And we can apply it to input stream samples by defining {{Windows}}. Isn't it what are you talking about? Second is about count(). Could it be a transformation function that returns a {{DataStream}} that can be printed or saved to a file then? And I can't imagine cases for the code fragment above (do you meant a collect() method instead of a print()?). Is it for retrieving only one sample to the driver from the whole stream? Not for making samples every 5 seconds? Thank you. > Introduce collect()/coun()/print() methods in DataStream API > ------------------------------------------------------------ > > Key: FLINK-3133 > URL: https://issues.apache.org/jira/browse/FLINK-3133 > Project: Flink > Issue Type: Improvement > Components: DataStream API, Streaming > Affects Versions: 0.10.0, 1.0.0, 0.10.1 > Reporter: Maximilian Michels > Assignee: Alexander Shoshin > Fix For: 1.0.0 > > > The DataSet API's methods {{collect()}}, {{count()}}, and {{print()}} should > be mirrored to the DataStream API. > The semantics of the calls are different. We need to be able to sample parts > of a stream, e.g. by supplying a time period in the arguments to the methods. > Collect/count/print should be lazily evaluated. Users should use the > {{StreamEnvironment}} to retrieve the results. > {code:java} > StreamExecutionEnvironment env = > StramEnvironment.getStreamExecutionEnvironment(); > DataStream<Integer> printSink = env.addSource(..).print(); > ResultQueryable queryObject = env.executeWithResultQueryable(); > List<Integer> sampled = queryObject.retrieve(printSink, Time.seconds(5)); > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)