Re: an enhancement idea

On 12/05/10 12:27 PM, Tom Lane wrote:
> John R Pierce<pierce@hogranch.com>  writes:
>> one of the reasons PostgreSQL is less popular with shared hosting
>> services is that there is insufficient isolation between database
>> users.  For instance, one user leaves a<Idle in TransactioN>  pending
>> due to sloppy programming, and the entire cluster eventually can't be
>> vacuumed.   There's numerous other places where the isolation between
>> postgres users is insufficient (visibility of information in pg_catalog,
>> for instance).
> If you want that level of isolation, you have to give each user his own
> cluster.

as postgresql is currently structured, yes, and further, each cluster
needs its own listener port which is, IMHO, rather ugly.

My idea of adding an 'instance' layer allows clusters to share ports.
in fact, the first generation of this idea was to fire up a cluster for
each user, but put them all under the common postmaster, which would
look up the database being connected to, and point the connection's
forked postgres server process at the proper cluster, much the way the
Oracle listener forks Oracle instances.