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https://issues.apache.org/jira/browse/DERBY-5448?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13122182#comment-13122182
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Myrna van Lunteren commented on DERBY-5448:
-------------------------------------------
One more thing I thought to mention: I've not seen deadlocks in this test since
I started running them (for QA cycle for 10.5, I think), but comments in the
test lead me to believe they may have been possible.
I'm referring to this section in the Tester1 class:
// Too many deadlocks amd locking issues if this is not
commented out
try {
connex.setAutoCommit(false);
} catch (Exception e) {
System.out.println("FAIL: " + getThread_id()
+ "'s setAutoCommit() failed:");
printException("setting AutoCommit", e);
}
// also set isolation level to
Connection.TRANSACTION_READ_UNCOMMITTED
// to reduce number of
// deadlocks
setIsolationLevel(Connection.TRANSACTION_READ_UNCOMMITTED);
So perhaps a different hardware/jvm combination is more/less likely to run into
deadlock situations...?
> 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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