问题描述：
当我们使用非系统用户查看Autotrace时，会出现下面的错误，提示PLUSTRACE角色未被激活，错误信息如下：
[oracle@strong ~]$ sqlplus scott/scott
SQL*Plus: Release 11.2.0.4.0 Production on Sat Sep 9 14:02:06 2017
Copyright (c) 1982, 2013, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> set autotrace on
SP2-0618: Cannot find the Session Identifier. Check PLUSTRACE role is enabled
SP2-0611: Error enabling STATISTICS report
SQL> 解决方案：
事实上PLUSTRACE角色并不存在，Oracle提供了对应的脚本，只要执行下即可，切换到系统用户SYS，执行下面的脚本，然后把PLUSTRACE授予Public，这样就可以访问了。
SQL> @?/sqlplus/admin/plustrce.sql
SQL> grant plustrace to public;