Events是Oracle的重要诊断工具，通过该工具寻求解决问题的方法。很多情况下需要通过Events设置来过滤所需的事件信息。比如之前我们为了收集控制信息使命令：alter session set events'immediate trace name controlf level 12'

关于Control file的dump级别

ALTER SESSION SET EVENTS 'immediate trace name controlf level n';

level 1 文件头信息
level 2 1 + 数据库信息 + 检查点信息
level 3 2 + ALL
level 12 3 + 更详细的记录。

关于File Header的dump级别

ALTER SESSION SET EVENTS 'immediate trace name file_hdrs level n';

level 1 控制文件中的文件头信息

level 2 1+文件头信息

level 3  2+数据文件头信息

在spfile中添加Events设置：

SQL> alter system set event='10841 trace name context forever' scope=spfile;
SQL> show parameter event
NAME                                 TYPE                              VALUE
------------------------------------ --------------------------------- ------------------------------
event                                string                            10841 trace name context forever

《DBA入门、进阶与诊断案例》中提到跟踪10841事件是解决Oracle 9i中JDBC Thin Driver问题的方法，如果在alter_<sid_name>.log文件中出现以下错误提示：

Wed Jan 7 17:17:08 2004
Errors in file /opt/oracle/admin/phsdb/udump/phsdb_ora_1775.trc:
ORA-00600: internal error code, arguments: [ttcgcshnd-1], [0], [], [], [], [], [], []
Wed Jan 7 17:17:18 2004
Errors in file /opt/oracle/admin/phsdb/udump/phsdb_ora_1777.trc:
ORA-00600: internal error code, arguments: [ttcgcshnd-1], [0], [], [], [], [], [], []
Wed Jan 7 17:17:24 2004
Errors in file /opt/oracle/admin/phsdb/udump/phsdb_ora_1783.trc:
ORA-00600: internal error code, arguments: [ttcgcshnd-1], [0], [], [], [], [], [], []
Wed Jan 7 17:17:31 2004
Errors in file /opt/oracle/admin/phsdb/udump/phsdb_ora_1785.trc:
ORA-00600: internal error code, arguments: [ttcgcshnd-1], [0], [], [], [], [], [], []
Wed Jan 7 17:17:39 2004
Errors in file /opt/oracle/admin/phsdb/udump/phsdb_ora_1777.trc:
ORA-00600: internal error code, arguments: [ttcgcshnd-1], [0], [], [], [], [], [], []
Wed Jan 7 17:17:45 2004
Errors in file /opt/oracle/admin/phsdb/udump/phsdb_ora_1783.trc:
ORA-00600: internal error code, arguments: [ttcgcshnd-1], [0], [], [], [], [], [], []
Wed Jan 7 17:17:52 2004
Errors in file /opt/oracle/admin/phsdb/udump/phsdb_ora_1787.trc:
ORA-00600: internal error code, arguments: [ttcgcshnd-1], [0], [], [], [], [], [], []
Wed Jan 7 17:18:11 2004
Errors in file /opt/oracle/admin/phsdb/udump/phsdb_ora_1791.trc:
ORA-00600: internal error code, arguments: [ttcgcshnd-1], [0], [], [], [], [], [], []
Wed Jan 7 17:18:19 2004
Errors in file /opt/oracle/admin/phsdb/udump/phsdb_ora_1785.trc:
ORA-00600: internal error code, arguments: [ttcgcshnd-1], [0], [], [], [], [], [], []

可能是遇到Bug 1725012，设置该事件后，可以屏蔽和解决这个内部错误，具提解决方式来源Metalink文档。

SQL> alter system reset event scope=spfile;
SQL> startup force
SQL> show parameter event
NAME                                 TYPE                              VALUE
------------------------------------ --------------------------------- ------------------------------
event                                string