I will be looking at this later in the week as of course my real work has interrupted :) Thanks for all of the valuable input!
Brrett ________________________________________ From: Rick Hillegas [[email protected]] Sent: Friday, March 29, 2013 2:10 PM To: [email protected] Subject: Re: Why is the optimizer choosing such a bad path On 3/29/13 9:30 AM, Mike Matrigali wrote: > On 3/29/2013 5:28 AM, Bergquist, Brett wrote: >> Mike I have a reproducible case but the database is 132GB so it is >> not practical. I am willing to dig in and try to help debug this. >> On the issue that was pointed to, Mamta seemed to have used a debug >> procedure that would print out more information on why the optimizer >> is choosing what it does. This might be useful in this case as well. >> >> So if someone can point me in the right area of the code to start >> looking and adding some debug that would be helpful. I have done >> some fixes for Derby in the past so I am able to build and debug Derby. >> > That's great. I am out of my depth debugging optimizer problems, > hopefully rick and/or mamta can help with that tool they were working > on. I think rick did some work to make it easier to turn on/off using > optional tools. > The simpler api to optimizer tracing is part of the 10.10.1 release candidate which we're testing now. Instructions on how to use it can be found in my 2013-03-14 comment on https://issues.apache.org/jira/browse/DERBY-6022 Hope this helps, -Rick
