[jira] [Comment Edited] (FLINK-2144) Incremental count, average, and variance for windows

["Wenlong Lyu (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-2144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15350396#comment-15350396 ] 

Wenlong Lyu edited comment on FLINK-2144 at 6/27/16 7:57 AM:
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we are also considering incremental aggregation solution for evicting window currently, evicting window must re-compute all the data of the window, no reducing state mechanism is available. It seems impossible to use fold function to solve the problem. [~aljoscha]


was (Author: dragon.l):
we also consider increment agg for sliding window currently, evicting window must re-compute all the data of the window, no reducing state mechanism is available. 

> Incremental count, average, and variance for windows
> ----------------------------------------------------
>
>                 Key: FLINK-2144
>                 URL: https://issues.apache.org/jira/browse/FLINK-2144
>             Project: Flink
>          Issue Type: New Feature
>          Components: Streaming
>            Reporter: Gabor Gevay
>            Priority: Minor
>              Labels: statistics
>
> By count I mean the number of elements in the window.
> These can be implemented very efficiently building on FLINK-2143:
> Store: O(1)
> Evict: O(1)
> emitWindow: O(1)



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