Re: Restricting schema sizes

Kieren Scott wrote:
> What is the best way to restrict/limit the size that a schema can grow
> too in Postgresql?
> ...
> The other option I can think of is writing a script that monitors the
> size of the objects
> within a schema. The danger here is that a user could potentially
> create a huge table
> as a result of a bad query (cartesian join etc) and fill the
> application tablespace / filesystem.

You have answered your own question here. There isn't any facility in
PostgreSQL yet to enforce disk space usage, so if this requirement is a
must it's something you'll have to build yourself. The
tablespace->filesystem mapping you suggested is probably a good idea to
house these things at, to prevent one user from taking out the main part
of the database with something they do.

One way that you can try to limit the damage of rogue queries on top of
that is to set statement_timeout so they just get cancelled if they run
for too long. If the tables are being populated by a single statement
and you set that to a moderate amount of time, that should be effective
at cutting off any of the really bad ones after they've run for a
while. You'll have to experiment at just how long that timeout should
be. If you set log_min_duration_statement (which is a general good idea
in this situation anyway) and look at what kind of runtime common
intense but not crippling queries take, that's one way to get feedback
on where the timeout should be.

--
Greg Smith, 2ndQuadrant US greg(at)2ndQuadrant(dot)com Baltimore, MD
PostgreSQL Training, Services and Support www.2ndQuadrant.us
Author, "PostgreSQL 9.0 High Performance" Pre-ordering at:
https://www.packtpub.com/postgresql-9-0-high-performance/book