We had multiple hanging problems on 18.104.22.168 RAC running on AIX 5.2. 22.214.171.124 and later 126.96.36.199 were better though we have had a hang or two. I can only remember the details for two of the three separate bugs that we hit and which support identified as the cause of our hung database. The first seems unlikely since you are using one-node RAC. In a RAC environment if too many sessions attempt to log on too concurrently the database can develop a problem trying to access the sequence generator behind v$session.audsid. Just increase the cache size from 20 to 1,000. (Support recommended 10k but that seems a little like overkill) The second was identified as not being a bug but a deadlock occurred on the rdbms base tables. Oracle is apparently unable to identify this condition like it can for user table access so it does not kill one of the sessions and roll it back automatically. However, you can however see the problem in the hang analyze dump. We hit at least one other identified bug but I do not remember the details at all. Next time before issuing any shutdown command run a hang analyze which will give you something to look at. If you cannot spot the problem in the trace then you upload the trace to support to give them something to work with. HTH -- Mark D Powell -- ________________________________ From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Ahmed Ullah Sent: Thursday, April 27, 2006 6:36 PM To: oracle-l@xxxxxxxxxxxxx Subject: DATABASE HANGS WITH SHUTDOWN IMMEDIATE Hello all: We have Oracle 188.8.131.52 database ( single Note RAC ). There were some heavy batch jobs running which cuased the db hang ( only sys connection was working ). We tried to bring down the database after cleaning all sessions. It did not go down with SHUTDOWN IMMEDIATE. We had to abort it. I tried to bring down the DB three times with SHUTDOWN IMMEDIATE it never went down. SMON was trying to cleanup the used extents ( Metalink Note - 1076161.6 ) as we could see in the alert log file - Waiting for smon to disable tx recovery. SQL> select count(block#) from fet$; COUNT(BLOCK#) ------------- 38 fet$ - free extents SQL> select count(block#) from uet$; COUNT(BLOCK#) ------------- 52905 uet$ - used extents We can share the alert log and system level 10 trace files if anyone wants. These traces were generated when db hung. Appreciate your help. Thanks, -ahmed _____________________________________________ "If we knew what it was we were doing, it wouldn't be called research, would it?" --Albert Einstein ________________________________ New Yahoo! Messenger with Voice. Call regular phones from your PC <http://us.rd.yahoo.com/mail_us/taglines/postman5/*http://us.rd.yahoo.co m/evt=39666/*http://messenger.yahoo.com> and save big.