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https://issues.apache.org/jira/browse/DERBY-5448?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13122212#comment-13122212
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Mike Matrigali commented on DERBY-5448:
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I agree that the deadlocks do not seem identity related given the trace. It
might shed light if anyone can reproduce with full lock tracing on and get a
full lock table dump.
it looks like muliple threads are doing "max's" while in a multi-statement
transaction and holding previous X row locks on the table leading
to classic user level deadlock.
There was a change to MAX in 10.8 ( DERBY-642), but I do not know if these
queries go through that code path. That would not explain
it if nstest is getting deadlock in 10.8 RC, but not in the initial 10.8
release.
> In the 10.8 branch, back out the concurrency improvements introduced by using
> SequenceUpdaters to allocate identity values.
> ---------------------------------------------------------------------------------------------------------------------------
>
> Key: DERBY-5448
> URL: https://issues.apache.org/jira/browse/DERBY-5448
> Project: Derby
> Issue Type: Bug
> Components: Documentation, SQL
> Affects Versions: 10.8.2.1
> Reporter: Rick Hillegas
> Fix For: 10.8.2.1
>
> Attachments: derby-5448-01-aa-backoutConcurrencyChanges.diff,
> derby-5448-02-aa-backoutDocsChanges.diff
>
>
> New errors were seen while running NsTest against the 10.8.2 release
> candidates. These errors are recorded as DERBY-5430 and DERBY-5422. The first
> error is a deadlock which occurs when inserting into the main table of the
> test. The second error is a problem clearing the identity cache. These errors
> have caused people to lose confidence in the concurrency improvements
> introduced by DERBY-4437. We should back the DERBY-4437 changes out of the
> 10.8 branch and use the trunk to continue debugging the problems disclosed by
> NsTest.
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