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.
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Greg Smith, 2ndQuadrant US greg@2ndQuadrant.com Baltimore, MD
PostgreSQL Training, Services and Support www.2ndQuadrant.us
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