[jira] [Resolved] (FLINK-2145) Median calculation for windows

["Gabor Gevay (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FLINK-2145?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Gabor Gevay resolved FLINK-2145.
--------------------------------
    Resolution: Won't Fix

I'm closing this, as it was based on assumptions of the old (pre-0.10) windowing. See https://github.com/apache/flink/pull/684#issuecomment-195402038

> Median calculation for windows
> ------------------------------
>
>                 Key: FLINK-2145
>                 URL: https://issues.apache.org/jira/browse/FLINK-2145
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Streaming
>            Reporter: Gabor Gevay
>            Assignee: Gabor Gevay
>            Priority: Minor
>              Labels: statistics
>
> The PreReducer for this has the following algorithm: We maintain two multisets (as, for example, balanced binary search trees), that always partition the elements of the current window to smaller-than-median and larger-than-median elements. At each store and evict, we can maintain this invariant with only O(1) multiset operations.
> Store: O(log N)
> Evict: O(log N)
> emitWindow: O(1)
> memory: O(N)



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