Re: PHP + Postgres: More than 1000 postmasters produce - Mailing list pgsql-general

Well, it seems for your application is better to limit php's persistent
connection pool as a quick measure.
Try to set these values to something sensible for you:

; Maximum number of persistent links.  -1 means no limit.
pgsql.max_persistent = 20
; Maximum number of links (persistent+non persistent).  -1 means no limit.
pgsql.max_links = 30

Or just disable persistent connections altogether, and see if that is
not resulting in better performance:

; Allow or prevent persistent links.
pgsql.allow_persistent = Off

In the long term look for some better connection pooling mechanism, I'm
sure you'll find something for PHP too (I'm not using php, maybe
somebody else on the list can help ?).

Cheers,
Csaba.

On Fri, 2004-02-20 at 16:32, Gellert, Andre wrote:
> Hello,
> we installed a new Postgres 7.4.0 on a Suse 9 system.
> This is used as a part of an extranet , based on Apache+PHP and has besides
> a ldap
> server no services running. The system has dual xeon 2ghz and 2GB RAM.
> When migrating all applications from 2 other postgres7.2 servers to the new
> one,
> we had heavy load problems.
> At the beginning there where problems with to much allocated shared memory,
> as the system was swapping 5-10 mb / sec . So we now reconfigured the
> shared_buffers to 2048, which should mean 2mb (linux=buffer each one kb) per
> process.
> We corrected higher values from sort_mem and vacuum_mem back to sort_mem=512
> and
>  vacuum_mem=8192 , too, to reduce memory usage, although we have
>  kernel.shmall = 1342177280 and kernel.shmmax = 1342177280 .
>
> Currenty i have limited the max_connections to 800, because every larger
> value results in
> a system load to 60+ and at least 20.000 context switches.
>
> My problem is, that our apache produces much more than 800 open connections,
>
> because we are using > 15 diff. databases and apache seems to keep
> connections to every
> database open , the same httpd-process has connected before.
> For now i solved it in a very dirty way, i limited the number and the
> lifetime
> of each httpd process with those values :
>  MaxKeepAliveRequests 10
>  KeepAliveTimeout 2
>  MaxClients 100
>  MaxRequestsPerChild 300
>
> We use php 4.3.4 and PHP 4.2.3 on the webservers. PHP ini says:
> [PostgresSQL]
> ; Allow or prevent persistent links.
> pgsql.allow_persistent = On
> ; Maximum number of persistent links.  -1 means no limit.
> pgsql.max_persistent = -1
> ; Maximum number of links (persistent+non persistent).  -1 means no limit.
> pgsql.max_links = -1
>
> We are now running for days with an extremly unstable database backend...
> Are 1.000 processes the natural limit on a linux based postgresql ?
> Can we realize a more efficient connection pooling/reusing ?
>
> thanks a lot for help and every idea is welcome,
> Andre
>
> BTW: Does anyone know commercial administration trainings in Germany, near
> Duesseldorf?
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org