[
https://issues.apache.org/jira/browse/HDFS-4103?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13537529#comment-13537529
]
Tsz Wo (Nicholas), SZE commented on HDFS-4103:
----------------------------------------------
Aaron, I am disappointed that you said you needed some more time to review the
patch. I posted a comment on Dec 3 that "This issue is the core part of the
Snapshot feature. The patch is getting close. If you want to review it, please
do so." However, you did not give any review comments until today, Dec 20.
I am sorry that we can't wait for you anymore. Hope you understand.
> Support O(1) snapshot creation
> ------------------------------
>
> Key: HDFS-4103
> URL: https://issues.apache.org/jira/browse/HDFS-4103
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: namenode
> Affects Versions: Snapshot (HDFS-2802)
> Reporter: Tsz Wo (Nicholas), SZE
> Assignee: Tsz Wo (Nicholas), SZE
> Attachments: h4103_20121129.patch, h4103_20121202b.patch,
> h4103_20121202.patch, h4103_20121209b.patch, h4103_20121209.patch,
> h4103_20121210b.patch, h4103_20121210.patch, h4103_20121211.patch,
> h4103_20121212b.patch, h4103_20121212.patch, h4103_20121213.patch,
> h4103_20121215b.patch, h4103_20121215.patch, h4103_20121216.patch,
> h4103_20121217b.patch, h4103_20121217.patch, h4103_20121218.patch,
> h4103_20121219.patch
>
>
> In our first snapshot implementation, snapshot creation runs in O(N) and
> occupies O(N) memory space, where N = # files + # directories + # symlinks in
> the snapshot. The advantages of the implementation are that there is no
> additional cost for the modifications after snapshots are created, and it
> leads to a simple implementation.
> In this JIRA, we optimize snapshot creation to O(1) although it introduces
> additional cost in the modifications after snapshots are created. Note that
> the INode is given as an assumption, otherwise, there is a non-constant cost
> to find the INode.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
