Revisiting the thread a month back or so, I'm still investigating performance problems with GiST indexes in Postgres.
Looking at http://wiki.postgresql.org/wiki/PostgreSQL_8.4_Open_Items I'd like to clarify the contrib/seg issue. Contrib/seg is vulnerable to pathological behaviour which is fixed by my second patch, which can be viewed as complete. Contrib/cube, being multi-dimensional, is not affected to any significant degree, so should not need alteration.
A second quite distinct issue is the general performance of GiST indexes which is also mentioned in the old thread linked from Open Items. For that, we have a test case at http://archives.postgresql.org/pgsql-performance/2009-04/msg00276.php for btree_gist indexes. I have a similar example with the bioseg GiST index. I have completely reimplemented the same algorithms in Java for algorithm investigation and instrumentation purposes, and it runs about a hundred times faster than in Postgres. I think this is a problem, and I'm willing to do some investigation to try and solve it.
Do you have a recommendation for how to go about profiling Postgres, what profiler to use, etc? I'm running on Debian Linux x86_64.
Matthew -- Jadzia: Don't forget the 34th rule of acquisition: Peace is good for business. Quark: That's the 35th. Jadzia: Oh yes, that's right. What's the 34th again? Quark: War is good for business. It's easy to get them mixed up. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
