Cause: The System Monitor process terminated abnormally.Action: Check the accompanying messages, if any, and the background process trace file. Correct the problem mentioned in the messages. Then shut down and restart the instance. If the trace file mentions any other background process messages, check the trace file for the mentioned process until the root message is found.查找trace file和alert log，会有发现的
Thread 1 advanced to log sequence 235 Current log# 1 seq# 235 mem# 0: /data/oracle/oradata/gisora/redo01.log Mon Dec 5 01:30:08 2005 Errors in file /data/oracle/admin/gisora/bdump/gisora_pmon_18457.trc:
Current log# 1 seq# 235 mem# 0: /data/oracle/oradata/gisora/redo01.log
Mon Dec 5 01:30:08 2005
Errors in file /data/oracle/admin/gisora/bdump/gisora_pmon_18457.trc:
导致oracle服务停止
个人理解是这样得