SQL> set time on
00:51:52 SQL> select count(*) from v$lock;
COUNT(*)
----------
35
00:55:10 SQL> select /*+ rule */ count(*) from v$lock;
COUNT(*)
----------
35
00:55:38 SQL>
官方的解决方法
Query Against v$lock Run from OEM Performs Slowly (文档 ID 1328789.1)select count(*) from v$lock 查询慢
原文：http://blog.51cto.com/roidba/2349243