数据库服务器事件：用来对数据库进行性能分析、调优和负载分析的工具。
主要分为两类，一是点分析，一是期分析。点分析是描述在瞬间发生的事件，例如一个错误发生时的分析，期分析是从开始到结束一个阶段的分析，例如一个事务的分析。
事件描述及类型：
1 Connection：Connection to a database. Point
2 Disconnect：Disconnection from a database. Point
3 ErrorStack：Code stack for core dump. Point
4 Migration：Session migration between shared server processes. Point
5 ApplReg：Application context information. Point
6 RowSource：Row information. For Oracle Server release 8.0.2 and higher, this also includes data about the execution plan. Point
7 SQLSegment：Text of SQL statement. Point
8 Parse：SQL parsing information. Duration
9 Execute：Information for execution of SQL. Duration
10 Fetch：Actual row retrieval information. Duration
11 LogicalTX：The first time a database command is performed that may change the database status. Duration
12 PhysicalTX：Event marking a definite change in database status. Duration
13 Wait：Generic WAIT event. Context is provided in the event strings. Point

event='10015 trace name context forever,level 10' 用来dump回滚段，
strings system01.dbf | grep _SYSSMU | cut -d $ -f 1 | sort -u这个命令也可以看。

检查具体的errnum用处，使用如下脚本：

SQL> declare
err_msg varchar2(1024);
begin
err_msg:=SQLERRM(-10231);
dbms_output.put_line(err_msg);
end;
/
ORA-10231: skip corrupted blocks on _table_scans_

PL/SQL 过程已成功完成。

SQL>
待续.....

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