[jira] [Commented] (DERBY-6283) indexStat daemon processing tables over and over even when there are no changes in the tables in soft upgraded database.

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    [ https://issues.apache.org/jira/browse/DERBY-6283?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13706076#comment-13706076 ] 

ASF subversion and git services commented on DERBY-6283:
--------------------------------------------------------

Commit 1502319 from mikem@apache.org
[ https://svn.apache.org/r1502319 ]

DERBY-6283 indexStat daemon processing tables over and over even when there are no changes in the tables in soft upgraded database.

Changed system to always drop orphaned stats during update statistics call.  

Without this change soft upgraded systems running on 10.8 or higher derby 
software, that had an orphaned statistic would spin forever in the index 
stat daemon due to the same problem fixed by DERBY-5680 for hard 
upgraded databases.
                
> indexStat daemon processing tables over and over even when there are no changes in the tables in soft upgraded database.
> ------------------------------------------------------------------------------------------------------------------------
>
>                 Key: DERBY-6283
>                 URL: https://issues.apache.org/jira/browse/DERBY-6283
>             Project: Derby
>          Issue Type: Bug
>          Components: Store
>    Affects Versions: 10.8.3.1, 10.9.2.2, 10.10.1.3, 10.11.0.0
>            Reporter: Mike Matrigali
>            Assignee: Mike Matrigali
>            Priority: Blocker
>              Labels: derby_triage10_11
>         Attachments: derby-6283.diff
>
>
> The fix for DERBY-5680 currently requires hard upgrade.  A soft upgrade database with an orphaned stat row, that can be caused by something like DERBY-5681, will cause DERBY to spin eating up 100% of a cpu and possibly all the disk bandwith of the disk where the database is located.
> We should implement a fix that can be applied to soft upgraded databases if at all possible.
> In soft upgraded databases we can no use the work around of dropping the statistics as it is not available
> to soft upgraded db's with version < 10.9.  The only current workaround is to disable background stats
> completely.  Dropping and recreating the suspect table may also work.

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