On Thu, Feb 25, 2010 at 6:42 PM, Bruce Momjian <bruce@momjian.us> wrote:
> Was there every any conclusion on this issue?
I don't think so.
...Robert
> ---------------------------------------------------------------------------
>
> Matthew Wakeling wrote:
>>
>> 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.
>>
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>
> --
> Bruce Momjian <bruce@momjian.us> http://momjian.us
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