SMON eating 90% CPU

I have the problem that after restart of my database (8.0.5.1.0 on Solaris) SMON is doing something with my TEMP tablespace since 15 hours. I read something about coalescing extents and so on, so I created a new tablespace (not temporary) and defined the new tablespace as the temporary tablespace for all users.
I also used dbms_system.set_ev to set the event 10061 to stop SMON doing the cleanup of temporary segments.
My question: None of the actions helped. My apps are damn slow, sometimes I see that SMON is blocking other sessions. What can I do to stop SMON cleaning up temporary segments? Do I have to shutdown, startup w/o opening and drop the old temp tablespace? And why is SMON doing this only after restart of database? During normal work, I never see SMON cleaning up temp segments.

Thank you in advance,

Hermann

P.S. I know that we are using a _very_ old version of Oracle but our apps are fixed to 8.0 Received on Thu Mar 11 2004 - 07:28:56 CST