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Posted to hdfs-issues@hadoop.apache.org by "Kihwal Lee (JIRA)" <ji...@apache.org> on 2015/03/05 00:36:39 UTC

[jira] [Commented] (HDFS-7433) DatanodeManager#datanodeMap should be a HashMap, not a TreeMap, to optimize lookup performance

    [ https://issues.apache.org/jira/browse/HDFS-7433?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14347784#comment-14347784 ] 

Kihwal Lee commented on HDFS-7433:
----------------------------------

[~daryn] Do you think HDFS-7434 was the cause of the test failure?

> DatanodeManager#datanodeMap should be a HashMap, not a TreeMap, to optimize lookup performance
> ----------------------------------------------------------------------------------------------
>
>                 Key: HDFS-7433
>                 URL: https://issues.apache.org/jira/browse/HDFS-7433
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: namenode
>    Affects Versions: 2.0.0-alpha, 3.0.0
>            Reporter: Daryn Sharp
>            Assignee: Daryn Sharp
>            Priority: Critical
>         Attachments: HDFS-7433.patch, HDFS-7433.patch, HDFS-7433.patch
>
>
> The datanode map is currently a {{TreeMap}}.  For many thousands of datanodes, tree lookups are ~10X more expensive than a {{HashMap}}.  Insertions and removals are up to 100X more expensive.



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