query memory consumption

Hey folks,

We are looking to optimize the query I was talking about last week
which is killing our system.

We have explain and analyze which tell us about the cost of a query
time-wise, but what does one use to determine (and trace / predict?)
memory consumption?

thanks,
-Alan

--
“Don't eat anything you've ever seen advertised on TV”
         - Michael Pollan, author of "In Defense of Food"