Please file a JIRA issue. I don't think preparing a query plan should consume that much memory, or generate that much garbage.
Brett Sent from my iPhone On Apr 18, 2010, at 1:41, Chris Wilson <[email protected]> wrote: > Hi Bryan and all, > > On Sat, 17 Apr 2010, Bryan Pendleton wrote: > >>> I think this could be a case where the query optimizer could use >>> some work? >>> Is it useful for me to file a bug report somewhere, e.g. in JIRA? >> >> Yes, it would be particularly helpful if you could provide a complete >> standalone test case which demonstrates the problem. > > I believe I have done so; the link that I provided in my email to the > sources of the test case from Subversion should run on any Unix system > with Bash, Sun Java and the Derby libraries available. It has four > source > files (a shell script and three SQL scripts) and a copy of the Derby > database to save you developers the time of reloading the fixture data > used in the test. > >> If that's not possible, then perhaps you could gather query plan >> output >> and post that; perhaps the Derby optimizer is choosing a particularly >> poor query plan. > > OK, this is interesting. With the default JVM settings, it crashes > with > OOM before outputting the query plan. However, with -Xmx1024m, it > finishes in reasonable time, and does output the plan, which I've > attached. > > I guess that means that the optimiser is just taking a lot of memory > to > optimise the query, and it spends forever in GC before finally > hitting OOM > and giving up when using the default settings? Does this bear looking > into? Should I file a JIRA issue? > > Also the recommended page at > (http://wiki.apache.org/db-derby/PerformanceDiagnosisTips) contains a > broken link to "Working with Derby properties" > (http://db.apache.org/derby/docs/dev/tuning/ctunsetprop34818.html) > which > is currently 404. > > Cheers, Chris. > -- > Aptivate | http://www.aptivate.org | Phone: +44 1223 760887 > The Humanitarian Centre, Fenner's, Gresham Road, Cambridge CB1 2ES > > Aptivate is a not-for-profit company registered in England and Wales > with company number 04980791. > <query-plan.txt>
