Re: PostgreSQL users on webhosting

Jeff Davis wrote:

>However, for truly good seperation, I recommend that you run a seperate
>instance of postgresql (with a seperate $PGDATA directory) for each
>user, and run it under the UID of that user. It requires a little more
>disk space per account, but in a dollar amount it's virtually zero with
>today's disk prices. You will be able to tie the user into filesystem
>quotas, etc., much more easily, and also you could tune the DBs to the
>individual users if needed.
>
>
Out of curiosity, what kind of performance hit (whether CPU, memory,
disk activity) is incurred with having a lot of postmasters running in
this kind of a setup versus one postmaster with lots of databases?  We
typically run one postmaster for a lot of separate web applications, but
I like the notion of a instance-per-user (for both security and
maintenance).  In the case of having several "big" databases on one
server, would tuning stragegies need to keep in mind the settings of
other instances, or would you just tune each one as if it were the only
one on the box and let the OS deal with memory+disk load of multiple
instances?

/hope this question makes sense, waiting for coffee to kick in