DBCC FREEPROCCACHE 
DBCC DROPCLEANBUFFERS 

一、翻页性能测试

1、Top

select top 10 *  
from message where  id not in  
(select top 20 id frommessage where classid=77 order by id desc ) 
 and classid=77 order by id desc 

2、Max/Top

select top 10 *  
from message where id <(select min(id) from messagewhere  id in(select top 20 id  
from message where classid=77 order by iddesc) ) 
 and classid=77 order by id desc 

3、row_number

select top 10 * from  
(select row_number()over(order by id desc) rownumber,*from  
message where classid=77)a where classid=77 and rownumber>20