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From "Andrew Wang (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HDFS-3976) SampleQuantiles#query is O(N^2) instead of O(N)
Date Tue, 25 Sep 2012 22:56:07 GMT

     [ https://issues.apache.org/jira/browse/HDFS-3976?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Andrew Wang updated HDFS-3976:

    Attachment: hdfs-3976-1.patch

Small patch. TestMutableMetrics still passes, so I think correctness is fine.

I can run a real performance test if people want to see that too, but it seems strictly better
to me.
> SampleQuantiles#query is O(N^2) instead of O(N)
> -----------------------------------------------
>                 Key: HDFS-3976
>                 URL: https://issues.apache.org/jira/browse/HDFS-3976
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>    Affects Versions: 2.0.3-alpha
>            Reporter: Andrew Wang
>            Assignee: Andrew Wang
>            Priority: Minor
>         Attachments: hdfs-3976-1.patch
> SampleQuantiles#query() does O(N) calls LinkedList#get() in a loop, rather than using
an iterator. This makes query O(N^2), rather than O(N).

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