Re: [ADMIN] shared_buffers and shmmax - Mailing list pgsql-docs

From Bruce Momjian
Subject Re: [ADMIN] shared_buffers and shmmax
Date
Msg-id 200812152323.mBFNN3Y25121@momjian.us
Whole thread Raw
In response to Re: [ADMIN] shared_buffers and shmmax  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: [ADMIN] shared_buffers and shmmax  (Alvaro Herrera <alvherre@commandprompt.com>)
List pgsql-docs
Tom Lane wrote:
> [ redirecting to pgsql-docs ]
>
> Valentin Bogdanov <valiouk@yahoo.co.uk> writes:
> >> From: dx k9 <bitsandbytes88@hotmail.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
simplyin 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.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +
Index: doc/src/sgml/runtime.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v
retrieving revision 1.422
diff -c -c -r1.422 runtime.sgml
*** doc/src/sgml/runtime.sgml    20 Nov 2008 11:48:26 -0000    1.422
--- doc/src/sgml/runtime.sgml    15 Dec 2008 23:22:24 -0000
***************
*** 1087,1093 ****
       <thead>
        <row>
         <entry>Name</>
!        <entry>Approximate multiplier (bytes per increment) as of 8.3</>
        </row>
       </thead>

--- 1087,1093 ----
       <thead>
        <row>
         <entry>Name</>
!        <entry>Additional bytes per object, as of 8.3</>
        </row>
       </thead>

***************
*** 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>

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