Re: Worse perfomance on 8.2.0 than on 7.4.14

--- Dave Cramer <pg(at)fastcrypt(dot)com> skrev:

>
> On 31-Dec-06, at 6:33 AM, Rolf Østvik wrote:
>
> >
> > Hi
> >
> > I have a simple query which uses 32ms on 7.4.14
> and 1015ms on 8.2.0.
> > I guess 7.4.14 creates a better execution plan
> than 8.2.0 for this
> > query but
> > i don't know how to get it to select a better one.
> > Explain analyse output will be found near the end
> of the e-mail.
> >
> > (I have simplified my real query to get it as
> simple as possible.
> > The original query
> > contain 6 tables and was acceptable on 7.4.2, but
> took far too long
> > on 8.1.4)
> >
> > I have made a test setup to compare 7.4.14, 8.1.4
> and 8.2.0.
> > 8.1.4 and 8.2.0 uses the same execution plan and
> same time to execute.
> >
> > postgresql.conf values i changed is
> > 7.4.14
> > Raised shared_buffers from 32MB to 128MB
> > Raised temp_buffers from 8MB to 32MB
> > 8.2.0
> > Raised shared_buffers from 32MB to 128MB
> > Raised temp_buffers from 8MB to 32MB
> > Raised work_mem from 1MB to 8MB
> >
> set effective_cache to 3G
> shared buffers should be 1G on this computer for 8.2

Thanks for the input. Did not have a big influence on
my specific problem but comments as this is very
valuable in the total setup of my server.

Best regards
Rolf Østvik

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