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From "Keith Turner (JIRA)" <>
Subject [jira] [Updated] (ACCUMULO-2172) Concurrent compactions before machine failure may cause uneeded recovery
Date Fri, 10 Jan 2014 19:49:51 GMT


Keith Turner updated ACCUMULO-2172:

    Affects Version/s: 1.5.0

seems this is an issue in 1.5.0 also.  Looked at 1.4.5-SNAP and its syncs these events.

> Concurrent compactions before machine failure may cause uneeded recovery
> ------------------------------------------------------------------------
>                 Key: ACCUMULO-2172
>                 URL:
>             Project: Accumulo
>          Issue Type: Bug
>    Affects Versions: 1.5.0
>            Reporter: Keith Turner
>             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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