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Re: [BULK] Problems with vacuum!

From: "Domenico Sgarbossa" <domenico(at)xtecnica(dot)com>
To: "Rosser Schwarz" <rschwarz(at)totalcardinc(dot)com>,<pgsql-performance(at)postgresql(dot)org>
Subject: Re: [BULK] Problems with vacuum!
Date: 2004-06-11 14:53:22
Message-ID: 004c01c44fc3$d7cdeaf0$70c8007e@xtecnica.it (view raw or flat)
Thread:
Lists: pgsql-performance
Thanks for your advice!

As I immagine the system released dinamically the shared memory .... the
problem is that
when , after vacuum, users runs my application (ERP) and the system swap on
disk so the global performance
decrease very fast until the system is so slow that I need to reboot the
server.

It seems that the cached memory isn't released by the system... so the
system begin to swap to disk!
The swap problem is very important, it makes useless run vacuum 'cause after
vacuum the system
begin to swap.... so my application runs very slow!

Could you explain me better your final advice please?

> Watching this "cached" value over normal usage of your machine to get
> a running average is how you come up with your effective_cache_size
> configuration directive.

what does this mean pratically?

thanks!

Distinti Saluti

Sgarbossa Domenico
X Tecnica S.R.L.
www.xtecnica.com
Tel: 049/9409154 - 049/5970297
Fax: 049/9400288

----- Original Message -----
From: "Rosser Schwarz" <rschwarz(at)totalcardinc(dot)com>
To: "'Domenico Sgarbossa'" <domenico(at)xtecnica(dot)com>;
<pgsql-performance(at)postgresql(dot)org>
Sent: Friday, June 11, 2004 4:09 PM
Subject: RE: [BULK] [PERFORM] Problems with vacuum!


> while you weren't looking, Domenico Sgarbossa wrote:
>
> Compare the "cached" values in each run of top.
>
> Before: 67828K cached
>
> After: 833896K cached
>
> The kernel is caching your tables for you.  That memory isn't actually
> being -used-, in the active, "a process has claimed this memory" sense.
> If a process comes along that needs more memory than free, the kernel
> will flush some of those cached pages (to swap?) to make room for
> whatever the memory requirements of the newcomer are.
>
> Watching this "cached" value over normal usage of your machine to get
> a running average is how you come up with your effective_cache_size
> configuration directive.
>
> /rls
>
> --
> Rosser Schwarz
> Total Card, Inc.
>
>
>




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Subject: Re: [BULK] Problems with vacuum!
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Subject: Re: Problems with vacuum!

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