减少聚集索引扫描成本如何降低下面提到查询如何通过使用SQL查询
DECLARE @PARAMVAL varchar(3)
set @PARAMVAL = 'CTD'
select * from MASTER_RECORD_TYPE where [email protected]
的聚集索引扫描的成本,如果我运行上面的查询它显示索引扫描99%
这里下面我贴我的索引表:
请在这里找到我下面的表特殊性
CREATE TABLE [dbo].[MASTER_RECORD_TYPE] ADD CONSTRAINT [PK_MASTER_REPORD_TYPE] PRIMARY KEY CLUSTERED
(
[Record_Type_Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 80) ON [PRIMARY]
GO
请告诉我如何降低索引扫描成本?
感谢您的及时回复,你可以请指导我创建一个覆盖非聚集索引,被列入该指数是什么键你能帮助我的队友对这个 – user1494292 2012-08-06 10:35:59
创建非聚集索引[MST_IDX_FOR_REC_TYPE ] ON [dbo]。[MASTER_RECORD_TYPE] ( \t [Record_Type_Code] ASC )WITH(PAD_INDEX = OFF,STATISTICS_NORECOMPUTE = OFF,SORT_IN_TEMPDB = OFF,IGNORE_DUP_KEY = OFF,DROP_EXISTING = OFF,ONLINE = OFF,ALLOW_ROW_LOCKS = ON,ALLOW_PAGE_LOCKS = ON)ON [PRIMARY ] GO现在索引扫描已经变成索引查找的100% – user1494292 2012-08-06 10:59:03
@ user1494292:好的 - 所以现在你有**索引寻找** - 这是最有效(最快)的方式来获取(几行的)数据 – 2012-08-06 11:04:55