Hibernate下DB2分页算法分析

DB2分页算法分析

性能对比结果：

Hibernate3性能差异：

Hibernate4性能差异：

分析过程

-- hibernate 3.6.10
-- DB2Dialect 分页算法
-- 1、首页
select * from ( select rownumber() over(ORDER BY a.sort_keys DESC ) AS rownumber_,
a.* FROM user_table_name a ORDER BY a.sort_keys DESC
) as temp_ where rownumber_ < 10
;
-- 2、分页
select * from ( select rownumber() over(ORDER BY a.sort_keys DESC ) AS rownumber_,
a.* FROM user_table_name a ORDER BY a.sort_keys DESC
) as temp_ where rownumber_ between 11 and 20
;
-------------------------------------------------------------
-- hibernate 4.3.11
-- DB2Dialect 分页算法
-- 1、首页
SELECT * FROM user_table_name ORDER BY sort_keys DESC
fetch first 10 rows ONLY
;
-- 2、分页
select * from ( select inner2_.*, rownumber() over(order by order of inner2_) as rownumber_ from (
SELECT * FROM user_table_name ORDER BY sort_keys DESC
fetch first 100  rows only ) as inner2_ ) as inner1_ where rownumber_ > 90
order by rownumber_
;