oracle分页优化

 

1.普通方式： select object_name,object_id,status from ( select object_name,object_id,status,rownum rn from( select object_name,object_id,status   from test_paging where owner='SYS'    AND object_type='TABLE' order by created ) where rownum<=500 ) where rn>=491 2.rowid方式： select object_name,object_id,status from ( select rid from ( select rid ,rownum rn from ( select rowid rid from test_paging where owner='SYS'   AND OBJECT_TYPE='TABLE' order by created ) where rownum<=500 ) where rn>=491 ) t,test_paging s where t.rid=s.rowid; 书上曾经提到： 当第一页查询的时候，普通方式可能要优于rowid方式 当越往后查询，明显rowid方式要快 可是我在环境上测试，发现第一中方式却比rowid的逻辑读要少。 我的表的构造来源all_objects, test_paging上索引是建立在（owner,object_type,created,status) 马上高手指点下。。。。