DBCC freeproccache 

DBCC dropcleanbuffers

1.set statistics IO {ON| OFF} /*Transact-SQL 语句生成的磁盘活动量的信息*/
2.set statistics time on {ON| OFF} /*显示分析、编译和执行各语句所需的毫秒数*/
3.set statistics profile on
4.set showplan_all on {ON| OFF} /*返回有关语句执行情况的详细信息，并估计语句对资源的需求*/

SQL分析好文分享

http://www.cnblogs.com/fish-li/archive/2011/06/06/2073626.html