Re: [ADMIN] shared_buffers and shmmax

Bruce Momjian wrote:
> Tom Lane wrote:
> > [ redirecting to pgsql-docs ]
> >
> > Valentin Bogdanov <valiouk(at)yahoo(dot)co(dot)uk> writes:
> > >> From: dx k9 <bitsandbytes88(at)hotmail(dot)com>
> > >> I'm trying to understand what the documentation means
> > >> by bytes per increment, what is the increment supposed to
> > >> be bytes, MB, or Kb.
> >
> > > shared_buffers is in disk block size, typically 8K, at least that's what it is on Linux platforms. shmmax is quite simply in bytes.
> >
> > The table the OP is looking at (table 17.2 in the 8.3 docs) predates
> > the ability to specify shared_buffers in KB or MB instead of
> > number-of-buffers. I agree it's not entirely obvious that what it
> > means is "multiply your setting in KB/MB by 8400/8192". Anybody have
> > an idea how to clarify things?
>
> I have updated the table title to be clearer.

I don't find it any clearer ... I think the missing clue is that if you
specify shared_buffers values in MB, you must divide the value by block
size.

> ***************
> *** 1119,1125 ****
>
> <row>
> <entry>Fixed space requirements</>
> ! <entry>770 kB</entry>
> </row>
> </tbody>
> </tgroup>
> --- 1119,1125 ----
>
> <row>
> <entry>Fixed space requirements</>
> ! <entry>770 k</entry>
> </row>
> </tbody>
> </tgroup>

This change is wrong, why did you do it?

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Alvaro Herrera http://www.CommandPrompt.com/
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