Re: Postgres Performance Tuning

On Tue, Apr 5, 2011 at 7:20 AM, Adarsh Sharma <adarsh(dot)sharma(at)orkash(dot)com> wrote:
> Scott Marlowe wrote:
>
> On Tue, Apr 5, 2011 at 1:33 AM, Adarsh Sharma <adarsh(dot)sharma(at)orkash(dot)com>
> wrote:
>
>
> [root(at)s8-mysd-2 ~]# free -m
>            total       used       free     shared    buffers     cached
> Mem:         15917      15826         90          0        101      15013
> -/+ buffers/cache:        711      15205
> Swap:        16394        143      16250
>
> It means 15 GB memory is cached.
>
>
> Note that the kernel takes all otherwise unused memory and uses it for
> cache. If, at any time a process needs more memory, the kernel just
> dumps some cached data and frees up the memory and hands it over, it's
> all automatic. As long as cache is large, things are OK. You need to
> be looking to see if you're IO bound or CPU bound first. so, vmstat
> (install the sysstat package) is the first thing to use.

BTW, just remembered that vmstat is it's own package, it's iostat and
sar that are in sysstat.

If you install sysstat, enable stats collecting by editing the
/etc/default/sysstat file and changing the ENABLED="false" to
ENABLED="true" and restarting the service with sudo
/etc/init.d/sysstat restart