[
https://issues.apache.org/jira/browse/FLINK-3133?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15674029#comment-15674029
]
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)
