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> De: Flavio Henrique Araque Gurgel <[email protected]> > À: pgsql-admin <[email protected]> > Cc: Nicolas Michel <[email protected]> > Sujet: Re: Memory Problem > Date: Sat, 4 Apr 2009 10:58:45 -0300 (BRT) > > > Hello! > > > Thank you very much. I didn't know that. I set my shmmax to 4000000000 but > > you're right, we will see to use a 64 bits system ;) > > My experience with this amount of memory in Debian Etch works much better in > a 64bit environment. BIGMEM kernel handles pages in a way that the > performance is a bit degraded. Thank you for this piece of information. > > > I wanted to give to postgres 4GB. So I tryied to set shmmax to 4Go : > > > > sysctl kernel.shmmax=4294967296 > > > > > > But it doesn't work : if I launch after this modification this command : > > > > sysctl kernel.shmmax > > > > it gives me this response : > > > > kernel.shmmax = 0 > > > > Why? Is there a limit to shmmax? > > I don't see limits in shmmax but the command you're typing is wrong. > To set a value you need to do: > sysctl -w kernel.shmmax=VALUE I read the man of sysctl and it seems that you're right. But I always set my sysctl variables without the -w switch and it seems that it used to work. > > or alternatively: > cat VALUE > /proc/sys/kernel/shmmax > > Don't forget to write in your /etc/sysctl.conf: > kernel.shmmax=VALUE > Without spaces. This will make your setting persistent. > > Regards > Flavio
