oracle autotrace

--=======================

-- 启用 AUTOTRACE功能

--=======================

AUTOTRACE是一个SQL*Plus工具,用于跟踪SQL的执行计划,收集执行时所耗用资源的统计信息,是SQL优化工具之一,下面给出启用

AUTOTRACE 功能步骤。

一、创建基础表

运行$ORACLE_HOME/rdbms/admin/utlxplan脚本来创建plan_table

scott@ORCL> conn system/redhat  --使用system帐户登陆

Connected.

system@ORCL> start $ORACLE_HOME/rdbms/admin/utlxplan --执行utlxplan脚本

Table created.

system@ORCL>
create public synonym plan_tablefor plan_table; 
--为表plan_table创建公共同义词

Synonym created.

system@ORCL>
grant all on plan_tableto
public;  --将同义词表plan_table授予给所有用户

Grant succeeded.

二、创建角色

运行$ORACLE_HOME/sqlplus/admin/plustrce.sql脚本

system@ORCL> conn
/ as sysdba   --使用sysdba帐户登陆

onnected.

sys@ORCL> start $ORACLE_HOME/sqlplus/admin/plustrce.sql  --执行创建角色的脚本

sys@ORCL>

sys@ORCL>
drop role plustrace;

drop
role plustrace

*

ERROR at line 1:

ORA-01919:role
'PLUSTRACE' doesnot exist

sys@ORCL>
create role plustrace;

Role created.

sys@ORCL>

sys@ORCL>
grant select on v_$sesstatto plustrace;

Grant succeeded.

sys@ORCL>
grant select on v_$statnameto plustrace;

Grant succeeded.

sys@ORCL>
grant select on v_$mystatto plustrace;

Grant succeeded.

sys@ORCL>
grant plustrace to dba
with admin option;

Grant succeeded.

三、角色的授予

在创建角色后，DBA首先被授予了该角色，且可以将角色授予其它组和用户。可以手工把plustrace授予给public,

则该数据库内所有的用户都将拥有plustrace角色的权限。也可以单独授予给某个组和用户

授予给所有用户

sys@ORCL>
grant plustrace to
public;

授予给单独用户

sys@ORCL>
grant plustrace to scott;

完成上述设置之后即可使用autotrace 功能

四、AUTOTRACE的几个选项

在sql提示符下输入set autot后将会给出设置autotrace的提示，如下

scott@ORCL>
set autot

Usage:
SET AUTOT[RACE] {OFF|
ON | TRACE[ONLY]} [EXP[LAIN]] [STAT[ISTICS]]

set autotrace off :缺省值，将不生成autotrace 报告

set autotrace on :包含执行计划和统计信息

set autotrace traceonly :等同于set autotrace on，但不显示查询输出的结果

set autotrace on explain :只显示优化器执行路径报告

set autotrace on statistics :只显示执行统计信息

scott@ORCL> set autotrace on;

scott@ORCL> select * from emp where ename='SCOTT';

EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO

---------- ---------- --------- ---------- --------- ---------- ---------- ----------

7788 SCOTT      ANALYST         7566 19-APR-87       3000                    20

Execution Plan

----------------------------------------------------------

Plan hash value: 3956160932

--------------------------------------------------------------------------

| Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time     |

--------------------------------------------------------------------------

|   0 | SELECT STATEMENT  |      |     1 |    37 |     3   (0)| 00:00:01 |

|*  1 |  TABLE ACCESS FULL| EMP  |     1 |    37 |     3   (0)| 00:00:01 |

--------------------------------------------------------------------------

Predicate Information (identified by operation id):

---------------------------------------------------

1 - filter("ENAME"='SCOTT')

Statistics

----------------------------------------------------------

0  recursive calls

0  db block gets

8  consistent gets

0  physical reads

0  redo size

824  bytes sent via SQL*Net to client

385  bytes received via SQL*Net from client

2  SQL*Net roundtrips to/from client

0  sorts (memory)

0  sorts (disk)

1  rows processed