PMON failed to acquire latch, see PMON dump

To implement the solution, execute the following steps::

1. In $ORACLE_HOME/network/admin/listener.ora, of the database where the Metadata Repository is to be loaded, add the line:
INBOUND_CONNECT_TIMEOUT_LISTENER = 0

2. In the Oracle Server 10g sqlnet.ora, add the line:
SQLNET.INBOUND_CONNECT_TIMEOUT = 0

3. Stop and restart the database and the listener for the changes to take effect

这是metalink上的：

Applies to:
Oracle Server - Enterprise Edition - Version: 10.2.0.1.0 to 10.2.0.3.0

This problem can occur on any platform.

Symptoms
Database Instance hangs and connections to database using 'sqlplus' are also not possible.

Checking alert.log we see following messages

PMON failed to acquire latch, see PMON dump
Fri Oct 5 10:33:00 2007
PMON failed to acquire latch, see PMON dump
Fri Oct 5 10:34:05 2007
PMON failed to acquire latch, see PMON dump
Errors in file /dwrac/BDUMP/dwhp_pmon_1912834.trc:

This will also dump a systemstate dump and the location will be mentioned in alert.log

 

Also at OS level, we see that MMAN is consuming lot of CPU.

 

Cause
Currently this issue is being worked upon by development in

 

Bug 6488694
- DATABSE HUNG WITH PMON FAILED TO ACQUIRE LATCH MESSAGE

 

 

Solution
As of now only workaround is to disable Automatic Shared Memory Management (

ASMM
) i.e Setting

SGA_TARGET=0

Also as per bug, you can can set following event and restart the instance

EVENT="10235 trace name context forever, level 2"

Development is suspecting memory corruption in this case. So with the above event, database might hit ORA-600 before spin. The trace file of ORA-600 would help investigate the issue. These trace files need to be sent to Oracle support for investigation.

Note : - Event 10235 with level 2 or higher can impact latch contention.Though may not be quite critical. In case you see latch contention then unset the event

References
Bug 6488694
- DATABSE HUNG WITH PMON FAILED TO ACQUIRE LATCH MESSAGE