> I'd like to look at it from the object level and see how much I/O is being
> done on specific table or index and then check which sessions are
> responsible for that.
>
> also, what's the catalog table you would recommend me to use if I want to
> see I/O activity on an object regardless of the session?
There is a bunch of interesting tables - see pg_stat_ and pg_statio_ tables.
Don't forget the values grow all the time, so you'll have to do snapshots
and subtract them. You could do that by hand, or use a tool for that.
There is a "pgstatspack" (should work fine, although it's not developed
since 8.1 AFAIK) and I'm working on an alternative tool with a web GUI
(http://sourceforge.net/projects/pgmonitor/). Still under development and
I know about several issues, but generally works (thanks in advance for
any feedback).
Tomas