DBMS_SUPPORT是Oracle提供的一个软件包。供内部支持人员使用以更有效地跟踪SQL.这个包没有正式的说明文件,默认情况下,系统不安装这个包。假如需要使用的话,需进行单独设置。
在你的$ORACLE_HOME/rdbms/admin/目录下应该存在dbmssupp.sql,prvtsupp.plb这两个文件。
SQL> connect / as sysdba Connected. SQL> @$ORACLE_HOME/rdbms/admin/dbmssupp.sql Package created.
Package body created.
SQL>
假如要其他用户也可以使用这个包,可以考虑提交如下授权操作(PUBLIC可以替换为具体的用户)并创建同义词:SQL> GRANT EXECUTE ON dbms_support TO PUBLIC;
Grant sUCceeded.
SQL> CREATE PUBLIC SYNONYM dbms_support FOR dbms_support;
DBMS_SUPPORT的结构并不复杂:SQL> desc DBMS_SUPPORT
FUNCTION MYSID RETURNS NUMBER FUNCTION PACKAGE_VERSION RETURNS VARCHAR2 PROCEDURE START_TRACE Argument Name Type In/Out Default?
WAITS BOOLEAN IN DEFAULT BINDS BOOLEAN IN DEFAULT PROCEDURE START_TRACE_IN_SESSION Argument Name Type In/Out Default?
SID NUMBER IN SERIAL NUMBER IN WAITS BOOLEAN IN DEFAULT BINDS BOOLEAN IN DEFAULT PROCEDURE STOP_TRACE PROCEDURE STOP_TRACE_IN_SESSION Argument Name Type In/Out Default?
SID NUMBER IN SERIAL NUMBER IN
SQL>
其中通过MYSID可以获得当前会话(Session)的SID(以及serial#):SQL> SELECT SYS.dbms_support.mysid FROM DUAL;
MYSID
25
SQL> SQL>SELECT SID, serial# FROM v$session WHERE SID = dbms_support.mysid;
SID SERIAL#
25 4328
SQL>通过package_version可以得到软件包所能支持的最低的PL/SQL的版本:SQL> SELECT dbms_support.package_version 2 FROM dual;
PACKAGE_VERSION
DBMS_SUPPORT Version 1.0 (17-Aug-1998) - Requires Oracle 7.2 - 8.0.5
如何激活SQL跟踪? START_TRACE有两个参数:WAITS和BINDS.其中WAITS默认为TRUE,BINDS默认为FALSE.假如简单的提交:SQL>EXECUTE dbms_support.start_trace;则默认激活10046事件,level 1.也即等同于:SQL>ALTER SESSION SET EVENTS '10046 trace name context forever, level 1';假如提交:SQL>EXECUTE dbms_support.start_trace (BINDS=>true);则激活10046事件,level 4.等同于:SQL>ALTER SESSION SET EVENTS '10046 trace name context forever, level 4';假如提交:SQL>EXECUTE dbms_support.start_trace (WAITS=>true);则激活10046事件,level 8.等同于:SQL>ALTER SESSION SET EVENTS '10046 trace name context forever, level 8';停止跟踪提交:SQL>EXECUTE dbms_support.stop_trace;
start_trace_in_session有四个参数,可参考上面DESCRIBE的输出。假如要跟踪其他用户的会话,就要用上它了。以上面的输出举例(需要SID和SERIAL#):SQL>EXECUTE dbms_support.start_trace_in_session (25, 4328, waits->true,binds=>true,);
上面这条命令和以下语句起到同样功能:SQL>EXECUTE dbms_system.set_ev (25, 4328, 10046, 4, 8);
停止跟踪提交:SQL>EXECUTE dbms_support.stop_trace_in_session (25, 4328);
其他问题
这个包从Oracle RDBMS 7.2 开始就有提供。但在某些版本/平台上可能不存在。
注:各个Level的基本解释:Level 0 = No statistics generated Level 1 = standard trace output including parsing, executes and fetches plus more. Level 2 = Same as level 1. Level 4 = Same as level 1 but includes bind information Level 8 = Same as level 1 but includes wait's information Level 12 = Same as level 1 but includes binds and waits