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https://issues.apache.org/jira/browse/DERBY-6510?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13935207#comment-13935207
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Mike Matrigali commented on DERBY-6510:
---------------------------------------

i see i missed some conversation in the list thread, that answered some of my 
questions.

I think it would help to understand the problem if you could give us how long 
it takes the 
optmizer work on that one query in a single user system.  If it takes 5 minutes 
single user
but seems to take hours multiuser sometime then that is one problem, if it 
takes hours
single user then maybe we concentrate on why it is being re-compiled more than 
once.

Also if it really is just one query a short term workaround might be to hand 
tune the query
with optimizer hints.

> Deby engine threads not making progress
> ---------------------------------------
>
>                 Key: DERBY-6510
>                 URL: https://issues.apache.org/jira/browse/DERBY-6510
>             Project: Derby
>          Issue Type: Bug
>          Components: Network Server
>    Affects Versions: 10.9.1.0
>         Environment: Oracle Solaris 10/9, Oracle M5000 32 CPU, 128GB memory, 
> 8GB allocated to Derby Network Server
>            Reporter: Brett Bergquist
>            Priority: Critical
>         Attachments: dbstate.log, derbystacktrace.txt
>
>
> We had an issue today in a production environment at a large customer site.   
> Basically 5 database interactions became stuck and are not progressing.   
> Part of the system dump performs a stack trace every few seconds for a period 
> of a minute on the Glassfish application server and the Derby database engine 
> (running in network server mode).   Also, the dump captures the current 
> transactions and the current lock table (ie. syscs_diag.transactions and 
> syscs_diag.lock_table).   We had to restart the system and in doing so, the 
> Derby database engine would not shutdown and had to be killed.
> The stack traces of the Derby engine show 5 threads that are basically making 
> no progress in that at each sample, they are at the same point, waiting.
> I will attach the stack traces as well as the state of the transactions and 
> locks.   
> Interesting is that the "derby.jdbc.xaTransactionTimeout =1800" is set, yet 
> the transactions did not timeout.  The timeout is for 30 minutes but the 
> transactions were in process for hours.



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