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From "ASF subversion and git services (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (ACCUMULO-2172) Concurrent compactions before machine failure may cause uneeded recovery
Date Fri, 10 Jan 2014 21:38:52 GMT

    [ https://issues.apache.org/jira/browse/ACCUMULO-2172?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13868335#comment-13868335
] 

ASF subversion and git services commented on ACCUMULO-2172:
-----------------------------------------------------------

Commit 3b41d37ed27b5dc8724b427ed6970b083464bd94 in branch refs/heads/1.6.0-SNAPSHOT from [~ecn]
[ https://git-wip-us.apache.org/repos/asf?p=accumulo.git;h=3b41d37 ]

ACCUMULO-2172 wait for minor compaction flags to be flushed to the WAL


> Concurrent compactions before machine failure may cause uneeded recovery
> ------------------------------------------------------------------------
>
>                 Key: ACCUMULO-2172
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-2172
>             Project: Accumulo
>          Issue Type: Bug
>    Affects Versions: 1.5.0
>            Reporter: Keith Turner
>            Assignee: Eric Newton
>             Fix For: 1.5.1, 1.6.0
>
>
> [~vines] noticed that minc finish events are not synced to the walog.  I was looking
into this issue to see if it was a problem and I noticed a possible issue w/ this.   If the
following sequence of events occurs, its possible that duplicate recovery may occur.
>  # Tablet T1 writes File F1 to metadata table after minor compaction
>  # T1 write minc finish event to walog (no sync is done and info not in walog)
>  # T1 adds F1 to set of files in tablets memory
>  # T1 major compacts F1 into F2
>  # Tablet server serving T1 fails (and nothing synced walog)
>  # T1 recovers data in F1 because there is no finish event or file in metadata table
> Step 2 must sync before step 3, because step 3 makes the file eligible for major compaction.
 Its seems like the sync could be done using group commit for efficiency.



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