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From "Jimmy Xiang (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-9696) Master recovery ignores online merge znode
Date Thu, 10 Oct 2013 00:13:42 GMT

    [ https://issues.apache.org/jira/browse/HBASE-9696?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13791025#comment-13791025
] 

Jimmy Xiang commented on HBASE-9696:
------------------------------------

[~jeffreyz], it won't get into this place actually.  In method
{noformat}
boolean processRegionInTransition(final String encodedRegionName,
      final HRegionInfo regionInfo)
{noformat}

If hri is null, it returns false.  For a new region to be created by a merge which is used
as the znode path, is not known to master during the recovery since it could have not been
written into meta yet.  Therefore, the two regions to be merged could be moved.

Yes, it's rare.  That's why ITBLL needs to loop several times to find it out.

> Master recovery ignores online merge znode
> ------------------------------------------
>
>                 Key: HBASE-9696
>                 URL: https://issues.apache.org/jira/browse/HBASE-9696
>             Project: HBase
>          Issue Type: Bug
>          Components: master, Region Assignment
>            Reporter: Jimmy Xiang
>            Assignee: Jimmy Xiang
>             Fix For: 0.98.0, 0.96.1
>
>         Attachments: trunk-9696.patch
>
>
> The online merge znode uses the new region to be created.  When master restarts, the
new region is still unknown if the merging is not completed. Therefore the znode is ignored,
which should not.  That means the two merging regions could be moved around.  This could cause
some data loss if we are not luck.



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