And how did you determine UNDO segments is your problem...? On 12/29/05, The Human Fly <sjaffarhussain@xxxxxxxxx> wrote: > > Hello Everbody, > > Our share trading application database, patch set 9205, running on AIX > 5.3 64bit with 12CPU + 30 GB Memory,. Everyday, during trading > beginning hours, end-users complains that the database is performing > very slow, like hang stage for some times. We noticed that Oracle has > brough many undo segs. online. As per Oracle Support, we have set an > databases event '10511' for SMON to prevent taking unused undo segs > offline, i.e. keeping always undo segs online. But, this event brought > some other problems. SMON is not offlining the undo segs. rather, what > we see is that a lot of expired undo segs and everyday brings arond 40 > undo segs. online and still the same story repeates. When we count for > online undo segs from dba_rollback_segs, what we see is around 100+ > undo segs. are online. > We have set session parameter around 1400 and our undo tablespace > size is 6.6 gb and undo retention is set to default, i.e. 3 hrs. > > Is there any one facing the similar kind of problem. If so, is there > any work around. We are thinking of going back to MUM, where we create > around 100 rollback segments manually and size them accordingly. Is > that a good idea? > > Thanks for your time. > > > > > -- > Best Regards, > Syed Jaffar Hussain > OCP 8i & 9i DBA, > Banque Saudi Fransi, > Saudi Arabia > > ---------------------------------------------------------------------------------- > "Winners don't do different things. They do things differently." > -- > //www.freelists.org/webpage/oracle-l > > >