| From: | Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: -HEAD planner issue wrt hash_joins on dbt3 ? |
| Date: | 2006-09-11 19:10:53 |
| Message-ID: | 4505B4BD.8070702@kaltenbrunner.cc |
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| Lists: | pgsql-hackers |
Tom Lane wrote:
> Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc> writes:
>> I'm about to do some benchmarking on -HEAD one some hardware I have
>> available and it seems I'm hitting a rather weird issue causing the osdl
>> dbt3 benchmark to run very slow and eating CPU time for hours ...
>
> Could we see the actual EXPLAIN ANALYZE results for the slow plan?
> I'm unconvinced by your "hash join is bad" analysis, especially in
> the cases where you're giving it lots of work_mem. I think it's got
> something to do with the different join orders. The rowcount estimates
> in the fast plan all seem pretty good, but I'm betting something is
> wrong with some of them in the slow case.
will do - but that will take a while - the slow one runs for 12h or so
even without explain analyze overhead ...
Stefan
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