large uga/pga and scan rates

I have come across a strange problem on one of my production machines and the more I think about it the more confused I'm getting (maybe the right approach is to act first, think later). The problem is coming from a LARGE group-by query (with functions in the select). Over time, the user process memory (Sun Solaris. Measured using ps -el) is growing ever larger. The size is consistent to what I read from v$sesstat (session uga memory, session pga memory). After a few hours, scan rates go through the roof.

Now, I thought that PGA size was fixed, and couldn't grow indefinitely. What is going on here and what can I do about it (besides killing the user or adding more memory).

Thanks. Received on Fri Dec 08 2000 - 10:18:42 CST