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https://issues.apache.org/jira/browse/HBASE-3872?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13123670#comment-13123670
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bluedavy commented on HBASE-3872:
---------------------------------
@stack
current patch will cause data-loss in this situation:
1. change the SplitTransaction just like @mingjian said;
2. then create a table & put some data in hbase shell;
3. split the table in hbase shell;
4. kill the region server hosted the table;
5. after master do servershutdownhandler,then the table can be wrote again,but
the data previous wrote to the table lost.
and in above code,if we don't kill the region server,then the parent region
cann't be wrote,even if restart the cluster.
> Hole in split transaction rollback; edits to .META. need to be rolled back
> even if it seems like they didn't make it
> --------------------------------------------------------------------------------------------------------------------
>
> Key: HBASE-3872
> URL: https://issues.apache.org/jira/browse/HBASE-3872
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Affects Versions: 0.90.3
> Reporter: stack
> Assignee: stack
> Priority: Blocker
> Fix For: 0.90.4
>
> Attachments: 3872-v2.txt, 3872.txt
>
>
> Saw this interesting one on a cluster of ours. The cluster was configured
> with too few handlers so lots of the phenomeneon where actions were queued
> but then by the time they got into the server and tried respond to the
> client, the client had disconnected because of the timeout of 60 seconds.
> Well, the meta edits for a split were queued at the regionserver carrying
> .META. and by the time it went to write back, the client had gone (the first
> insert of parent offline with daughter regions added as info:splitA and
> info:splitB). The client presumed the edits failed and 'successfully' rolled
> back the transaction (failing to undo .META. edits thinking they didn't go
> through).
> A few minutes later the .META. scanner on master runs. It sees 'no
> references' in daughters -- the daughters had been cleaned up as part of the
> split transaction rollback -- so it thinks its safe to delete the parent.
> Two things:
> + Tighten up check in master... need to check daughter region at least exists
> and possibly the daughter region has an entry in .META.
> + Dependent on the edit that fails, schedule rollback edits though it will
> seem like they didn't go through.
> This is pretty critical one.
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