Unfortunately, introducing something into the production environment is not 
possible.  I am in the process of trying to build a simulation of that 
environment but that is also difficult as the application is an Element 
Management System and in the network there are about 40K pieces of our 
equipment that are being monitored and receiving data from with provisioning of 
additional services on the equipment or new equipment ever few minutes.  
Getting a lab setup with that is being a challenge (simulating 40K pieces of IP 
addressable equipment that responds to management request via SNMP is not 
trivial).

But the patch will give me an idea of where you were looking.   So from the 
comment in the JIRA, it appears that you were testing with a hard limit to the 
optimizer timeout.   So am I correct that in the 10.9 release timeframe, there 
is no such hard limit?

-----Original Message-----
From: Bryan Pendleton [mailto:[email protected]] 
Sent: Friday, March 14, 2014 10:10 AM
To: [email protected]
Subject: Re: I need help diagnosing a Derby engine problem where threads are 
not progressing

>>> My assumption is that there is a possibility that the optimization 
>>> may get into a state where it may take a very long time to complete 
>>> or may even be looping.

>>> So what I would like to explore is under what conditions could the 
>>> optimizer get into a state where it might loop or make no progress 
>>> for a very long period of time.

Are you able to try the patch for DERBY-2130 in your environment?

https://issues.apache.org/jira/browse/DERBY-2130

At the time that I was wrestling with this problem (years ago, sorry), I was 
experiencing great instability in optimization times.

Sometimes it would run in a few seconds.

Sometimes it would take 15 minutes.

If you can provide any feedback on whether the DERBY-2130 change alters the 
behaviors that you see, that would be great!

bryan

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