Re: Postgres tiene alguna recomendacion para la

hola a todos los listeros de postgreSQL

he seguido investigando acerca de la configuracion de postgres, en esta
pagina me dice:

http://www.lyris.com/lm_help/7.8/tuning_postgresql.html

1. Increase the buffer size. Postgres uses a shared memory segment among
its subthreads to buffer data in memory. The default is 512k, which is
inadequate. On many of our installs, we've bumped it to ~16M, which is
still small. If you can spare enough memory to fit your whole database in
memory, do so. Each buffer is 8 kb, so set it to:

shared_buffers = (the lesser of
(total memory you can spare) and
(size of database + 512k)
) / 8192

este tamaño de la base de datos a que se referira en esta parte.
Att,
TANIA GUTIERREZ

> On Fri, Aug 06, 2004 at 06:05:29PM -0500, tgutierrez(at)unipamplona(dot)edu(dot)co
> wrote:
>> Saludos..
>>
>> No he visto que configuren la variable SHMMAX más de 256 MB
>> Trabajan con 32, 64, 128 y 256
>>
>> En este enlace muestran que esa variable es muy importante en postgresql
>> y Me gustaria saber de que depende la configuracion de esa Variable si
>> de
>> la memosria swap, la memoria ram... o de que especificamente...
>>
>> http://developer.postgresql.org/docs/postgres/kernel-resources.html
>
> Bueno, en ese mismo enlace se explica cual es la importancia de SHMMAX
>
> The most important shared memory parameter is SHMMAX, the maximum size,
> in bytes, of a shared memory segment. If you get an error message from
> shmget like Invalid argument, it is possible that this limit has been
> exceeded. The size of the required shared memory segment varies both
> with the number of requested buffers (-B option) and the number of
> allowed connections (-N option), although the former is the most
> significant. (You can, as a temporary solution, lower these settings to
> eliminate the failure.) As a rough approximation, you can estimate the
> required segment size by multiplying the number of buffers and the block
> size (8 kB by default) plus ample overhead (at least half a megabyte).
> Any error message you might get will contain the size of the failed
> allocation request.
>
>
> Como ves no tiene nada que ver con ningun parametro fisico o de
> configuracion del sistema operativo. Depende de la cantidad de buffers.
>
> --
> Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
> Bob [Floyd] used to say that he was planning to get a Ph.D. by the "green
> stamp method," namely by saving envelopes addressed to him as 'Dr. Floyd'.
> After collecting 500 such letters, he mused, a university somewhere in
> Arizona would probably grant him a degree. (Don Knuth)
>