Re: PostgreSQL Performance on OpenBSD - Mailing list pgsql-general

From Bruce Momjian
Subject Re: PostgreSQL Performance on OpenBSD
Date
Msg-id 200305250206.h4P26GN23042@candle.pha.pa.us
Whole thread Raw
In response to Re: PostgreSQL Performance on OpenBSD  (Martin Foster <martin@ethereal-realms.org>)
List pgsql-general
Are these different from what is already in our docs?

---------------------------------------------------------------------------

Martin Foster wrote:
> Chris Palmer wrote:
> > Martin Foster writes:
> >
> >
> >>However are the above numbers realistic?    This would require some
> >>fairly customized kernels for OpenBSD to allow for numbers
> >>that high as well?
> >
> >
> > What kernel parameter would need to be changed besides BUFCACHEPERCENT
> > (which defaults to 5%)? That's one small customization.
> >
> >
>
> # PostGRE SQL specific
> options         SYSVSHM
> options         SHMMAXPGS=4096
> options         SHMSEG=256
>
> options         SYSVSEM
> options         SEMMNI=512
> options         SEMMNS=1024
> options         SEMMNU=512
> options         SEMMAP=512
>
> All of these options are required in order to start raising the values
> of shared_buffers and most probably sort_mem.   Seems that PostgreSQL
> uses Posix extensions which are not very well represented in most BSD
> kernels.
>
> As a result, you need to manually raise the values above in order to get
> higher values.   If memory serves, the above was necessary to have 256
> connections with 512 shared_buffers.
>
>     Martin Foster
>     Creator/Designer Ethereal Realms
>     martin@ethereal-realms.org
>
>
>
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