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https://issues.apache.org/jira/browse/DERBY-5073?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13005764#comment-13005764
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Knut Anders Hatlen commented on DERBY-5073:
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Thanks for the feedback, Bryan and Kathey. I'll polish the patch and
incorporate the repros attached to this issue and DERBY-3980 into a JUnit test
that can run as part of the regression test suite.
Since we don't know for sure that the repro I attached reproduces the exact
same problem as originally reported, we should probably check in the fix under
DERBY-3980 and mark that issue as resolved. When Karl gets a chance to verify
that this also fixes the problem he saw, we can close this issue as a duplicate
of DERBY-3980.
And, yes, I'll annotate the deadlock detection code with comments reflecting my
understanding of what it does and how it should work. Good idea. Thanks!
> Derby deadlocks without recourse on simultaneous correlated subqueries
> ----------------------------------------------------------------------
>
> Key: DERBY-5073
> URL: https://issues.apache.org/jira/browse/DERBY-5073
> Project: Derby
> Issue Type: Bug
> Components: Services
> Affects Versions: 10.0.2.1, 10.1.2.1, 10.2.2.0, 10.3.3.0, 10.4.2.0,
> 10.5.3.0, 10.6.2.1, 10.7.1.1, 10.8.0.0
> Reporter: Karl Wright
> Attachments: Derby5073.java, derby-5073-1a.diff, derby-5073-1b.diff
>
>
> When the following two queries are run against tables that contain the
> necessary fields, using multiple threads, Derby deadlocks and none of the
> queries ever returns. Derby apparently detects no deadlock condition, either.
> SELECT t0.* FROM jobqueue t0 WHERE EXISTS(SELECT 'x' FROM carrydown t1 WHERE
> t1.parentidhash IN (?) AND t1.childidhash=t0.dochash AND t0.jobid=t1.jobid)
> AND t0.jobid=?
> SELECT t0.* FROM jobqueue t0 WHERE EXISTS(SELECT 'x' FROM carrydown t1 WHERE
> t1.parentidhash IN (?) AND t1.childidhash=t0.dochash AND t0.jobid=t1.jobid
> AND t1.newField=?) AND t0.jobid=?
> This code comes from Apache ManifoldCF, and has occurred when there are five
> or more threads trying to execute these two queries at the same time.
> Originally we found this on 10.5.3.0. It was hoped that 10.7.1.1 would fix
> the problem, but it hasn't.
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