weird pga swelling

I'm experiencing a weird issue I've never encountered before. One of my clients runs a moderately active database being connected to by a group of webservers running mod_perl, making a 'standard' set of queries to generate dynamic content. 'standard' in this sense means that the queries are unchanged for many months, none of them are particularly expensive. Randomly (once/twice week) I'm having shadow processes (LOCAL=NO sessions) whose PGA is welling to huge sizes. I am measuring this with pmem. I see things like:

3606: oracleFLPDT (LOCAL=NO)

Address   Kbytes Resident Shared Private Permissions       Mapped File
00010000   24776   19960   19960       - read/exec         oracle
01850000     240     240     208      32 read/write/exec   oracle
0188C000 1083848  946408       -  946408 read/write/exec    [ heap ]
80000000 1143448 1143448 1143448       - read/write/exec/shared  [shmid=0x2db5]

That's 1G of private heap usage by that one process. These sessions are not stuck running any particular sql, I have caught them executing any and all of the standard application code and they don't seem to be spinning on any particular query.

Any thoughts? This seems like a PGA memory leak to me.

// George Schlossnagle
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Received on Wed Dec 26 2001 - 20:54:18 CST