RE: Troubles with performances

Warren Vanichuk <pyber@street-light.com>

From: Warren Vanichuk <pyber@street-light.com>
To: "Mikheev, Vadim" <vmikheev@SECTORBASE.COM>
Cc: pgsql-general <pgsql-general@postgresql.org>
Date: 2001-01-18T20:04:44Z
Lists: pgsql-general
> > >> I use PostGreSQL with a Web server which receive 200 HTTP 
> > >> simultaneous queries.
> > > 
> > > With what opts do you start postmaster?
> > -F to disable fsync()
> > I don't know if I have to use the -B and -S options to change 
> > the memory use...
> 
> With 200 simult connections I would recomment to use
> -N 256 -B 16384

As we are about the same load, and I am always interested in more
performance, I increased the value of my -B to what you suggested, but I
generate the following error :

IpcMemoryCreate: shmget failed (Invalid argument) key=5432001, size=143193088, permission=600
This type of error is usually caused by an improper
shared memory or System V IPC semaphore configuration.
For more information, see the FAQ and platform-specific
FAQ's in the source directory pgsql/doc or on our
web site at http://www.postgresql.org.
FATAL 1:  ShmemCreate: cannot create region

I checked the Linux FAQ and the only thing related to this issue says that I
don't have shared memory turned on, which I'm pretty sure I do, considering
it's running..  ;)

This is a PostgreSQL 7.0.3 installed on a Debian (Stable) box, running Linux
2.2.18.  The machine has 1GB of memory, and is compiled for 32,768 file
descriptors.  The startup options I am using for PostgreSQL are :

-o -F -B 2048 -N 512 -S 4096

Opinions or suggestions? :)

Sincerely, Warren