一、启用Autotrace功能。

使用ORACLE的AUTOTRACE功能可以自动跟踪SQL语句并可以根据选项生成执行计划。
任何以SQL*PLUS连接的session都可以用Autotrace,不过还是要做一些设置的，否则可能报错。
1、报错示例：

SQL :> set autotrace on;

SP2-0613: Unable to verify PLAN_TABLE format or existence

SP2-0611: Error enabling EXPLAIN report

SP2-0618: Cannot find the Session Identifier. Check PLUSTRACE role is enabled

SP2-0611: Error enabling STATISTICS report
*******************************************************************************

SQL> set autotrace on;

SP2-0613: 无法验证 PLAN_TABLE 格式或实体

SP2-0611: 启用EXPLAIN报告时出现错误

SP2-0618: 无法找到会话标识符。启用检查 PLUSTRACE 角色

SP2-0611: 启用STATISTICS报告时出现错误


该错误的的主要原因是由于当前用户下没有PLAN_TABLE这张表及相应的PLUSTRACE角色权限。

2、解决方法：

A．以SYS用户登录：

oracle>sqlplus '/ as sysdba';

B．运行utlxplan.sql($ORACLE_HOME/rdbms/admin下) 脚本创建 PLAN_TABLE；
grant all on plan_table to scott;

C．通过执行 plustrce.sql($ORACLE_HOME/sqlplus/admin/plustrce.sql)脚本创建 plustrace

角色
grant plustrace to scott;
grant select any dictionary to scott;

二、设置Autotrace的命令。

Eg：SET AUTOTRACE ON

set timing on
alter session set time_statistics=true;

三、Autotrace执行计划的各列的涵义

四、AUTOTRACE Statistics常用列解释

======================================================

set autotrace 报错sp2-0613&sp2-0618

同事创建了role plustrace，使用system登录可以使用autotrace。
但以普通用户test登录时，报错：

SQL> connect test/test
Connected.

SQL> set autotrace on
SP2-0613: Unable to verify PLAN_TABLE format or existence
SP2-0611: Error enabling EXPLAIN report
SP2-0618: Cannot find the Session Identifier.  Check PLUSTRACE role is enabled
SP2-0611: Error enabling STATISTICS report

检查角色设置
SQL> select * from user_role_privs;

USERNAME                       GRANTED_ROLE                   ADM DEF OS_
------------------------------ ------------------------------ --- --- ---
TEST                          CONNECT                        NO  YES NO
TEST                           PLUSTRACE                      NO  YES NO
TEST                           RESOURCE                       NO  YES NO

检查表
SQL> select synonym_name,table_name,table_owner from all_synonyms where synonym_name = 'PLAN_TABLE';

no rows selected

应是表PLAN_TABLE没有赋予plustrace select权限。

SQL> connect system/manager as sydba

Connected.

SQL> create public synonym plan_table for plan_table;

Synonym created.

SQL> grant all on plan_table to public;

Grant succeeded.

再试：
SQL> connect test/test
Connected.

SQL> set autotrace on
SP2-0618: Cannot find the Session Identifier.  Check PLUSTRACE role is enabled
SP2-0611: Error enabling STATISTICS report

网上查找，tom说了：
http://asktom.oracle.com/pls/ask/f?p=4950:8:::::F4950_P8_DISPLAYID:5671636641855

Followup:

look up a couple of reviews.

I believe you have slightly mismatched versions of SQLPlus and database.

9203 and up use v$mystat
9202 and before use v$session

9201 client and lower queries v$session
9203 client and higher queries v$mystat

make sure plustrace has select on v$mystat and v$session or use the same version
of sqlplus as database.

我的Oracle server和SQL*Plus的版本都是9.0.2.4.0,找到原因了

SQL> connect system/manager as sydba

Connected.

SQL> grant select on v_$mystat to plustrace;

Grant succeeded.

SQL> connect test/test

Connected.

SQL> set autotrace on
成功！