Re: -HEAD planner issue wrt hash_joins on dbt3 ? - Mailing list pgsql-hackers

From Stefan Kaltenbrunner
Subject Re: -HEAD planner issue wrt hash_joins on dbt3 ?
Date
Msg-id 4505B4BD.8070702@kaltenbrunner.cc
Whole thread Raw
In response to Re: -HEAD planner issue wrt hash_joins on dbt3 ?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:
> Stefan Kaltenbrunner <stefan@kaltenbrunner.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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