hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Hairong Kuang (Commented) (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-2476) More CPU efficient data structure for under-replicated/over-replicated/invalidate blocks
Date Thu, 03 Nov 2011 16:37:32 GMT

    [ https://issues.apache.org/jira/browse/HDFS-2476?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13143294#comment-13143294
] 

Hairong Kuang commented on HDFS-2476:
-------------------------------------

Todd, Steve, how does the latest patch look to you? Could any one of you +1 it? Thank you
very much.
                
> More CPU efficient data structure for under-replicated/over-replicated/invalidate blocks
> ----------------------------------------------------------------------------------------
>
>                 Key: HDFS-2476
>                 URL: https://issues.apache.org/jira/browse/HDFS-2476
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>          Components: name-node
>            Reporter: Tomasz Nykiel
>            Assignee: Tomasz Nykiel
>         Attachments: hashStructures.patch, hashStructures.patch-2, hashStructures.patch-3,
hashStructures.patch-4, hashStructures.patch-5, hashStructures.patch-6
>
>
> This patch introduces two hash data structures for storing under-replicated, over-replicated
and invalidated blocks. 
> 1. LightWeightHashSet
> 2. LightWeightLinkedSet
> Currently in all these cases we are using java.util.TreeSet which adds unnecessary overhead.
> The main bottlenecks addressed by this patch are:
> -cluster instability times, when these queues (especially under-replicated) tend to grow
quite drastically,
> -initial cluster startup, when the queues are initialized, after leaving safemode,
> -block reports,
> -explicit acks for block addition and deletion
> 1. The introduced structures are CPU-optimized.
> 2. They shrink and expand according to current capacity.
> 3. Add/contains/delete ops are performed in O(1) time (unlike current log n for TreeSet).
> 4. The sets are equipped with fast access methods for polling a number of elements (get+remove),
which are used for handling the queues.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message