PMON failed to acquire latch, see PMON dump
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??? 今天在關閉數據庫的時候，shutdown immediate之后系統就hang住了，其他進程也連不上庫。查看了alert.log日志，發現大量出現“PMON failed to acquire latch, see PMON dump”這個錯誤，到網上查了一下，據說是個bug，在一篇博文上找到了解決的辦法：
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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
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這是metalink上的：
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Applies to:
Oracle Server - Enterprise Edition - Version: 10.2.0.1.0 to 10.2.0.3.0
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This problem can occur on any platform.
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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
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Bug 6488694
- DATABSE HUNG WITH PMON FAILED TO ACQUIRE LATCH MESSAGE
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Solution
As of now only workaround is to disable Automatic Shared Memory Management (
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ASMM
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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"
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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
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??? 最后沒辦法，hang住之后系統sys用戶都登不進，無法使用任何操作，只能重啟機器之后數據庫恢復正常。希望加了那兩個參數之后不要再發生這樣的Bug，雖然對數據庫的危害不大，但是需要重啟機器還是比較嚴重的。
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