Sean Chittenden wrote:
>
> I looked through the src/doc/runtime.sgml for a good place to stick
> this and couldn't find a place that this seemed appropriate, but on
> FreeBSD, this can be determined with a great deal of precision in a
> programmatic manner:
>
> echo "effective_cache_size = $((`sysctl -n vfs.hibufspace` / 8192))"
>
> The same OID is available via C too. It'd be slick if PostgreSQL
> could tune itself (on FreeBSD) at initdb time with the above code. If
> Linux exports this info via /proc and can whip out the appropriate
> magic, even better. An uncommented out good guess that shows up in
> postgresql.conf would be stellar and quite possible with the use of
> sed.
>
> Maybe an initdb switch could be added to have initdb tune the config
> it generates? If a -n is added, have it generate a config and toss it
> to stdout?
>
>
> case `uname` in
> "FreeBSD")
> echo "effective_cache_size = $((`sysctl -n vfs.hibufspace` / 8192))"
> ;;
> *)
> echo "Unable to automatically determine the effective cache size" >> /dev/stderr
> ;;
> esac
>
>
> -sc
>
Simplest way may be to create a 'auto-tune' directory with scripts for
configured platforms. When postgres installs the databases, it checks
for 'tune.xxx' and if found uses that to generate the script itself?
This would allow for defaults on platforms that do not have them and
optimization for those that do.
Martin Foster
Creator/Designer Ethereal Realms
martin@ethereal-realms.org