Question

这是我桌子的构造

CREATE TABLE [dbo].[InterfaceMeraAdReport_CAV](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [reportID] [nvarchar](100) NOT NULL,
    [FromTime] [nvarchar](100) NOT NULL,
    [ToTime] [nvarchar](100) NOT NULL,
    [Customer] [nvarchar](100) NOT NULL,
    [Area] [nvarchar](100) NOT NULL,
    [Vendor] [nvarchar](100) NOT NULL,
    [SuccessCalls] [nvarchar](100) NOT NULL,
    [TotalCalls] [nvarchar](100) NOT NULL,
    [TotalMins] [nvarchar](100) NOT NULL,
    [ASR] [nvarchar](100) NOT NULL,
    [ACD] [nvarchar](100) NOT NULL,
    [Fee] [nvarchar](100) NOT NULL,
    [Cost] [nvarchar](100) NOT NULL,
    [Profix] [nvarchar](100) NOT NULL,
 CONSTRAINT [PK_MeraAdvReport_CA] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

和两个最常用的查询是这种形式：一个

select  Customer,vendor,SUM(cast(SuccessCalls as int)) as successCalls,
SUM(cast(TotalCalls as int)) as TotalCalls,
SUM(cast(TotalMins as decimal(18,2))) as TotalMins,
case when  SUM(cast(TotalCalls as decimal(18,2)))  = 0  then 0.0 else (SUM(cast(SuccessCalls as decimal(18,2))) /  SUM(cast(TotalCalls as decimal(18,2)))) end as ASR,
case when  SUM(cast(SuccessCalls as decimal(18,2)))  = 0  then 0.0 else (SUM(cast(TotalMins as decimal(18,2))) /  SUM(cast(SuccessCalls as decimal(18,2)))) end as ACD,
SUM(cast(Profix as decimal(18,2))) as profix
from InterfaceMeraAdReport_CAV
where FromTime >= '20140128020000' and ToTime <= '20140128030000' 
 and Customer= '01.2136'  and Area  in ('62817','62818','62819','62859','62877','62878','62879') 
group by Customer,Vendor

两个

select Customer,SUM(cast(SuccessCalls as int)) as successCalls,
SUM(cast(TotalCalls as int)) as TotalCalls,
SUM(cast(TotalMins as decimal(18,2))) as TotalMins,
case when  SUM(cast(TotalCalls as decimal(18,2)))  = 0  then 0.0 else (SUM(cast(SuccessCalls as decimal(18,2))) /  SUM(cast(TotalCalls as decimal(18,2)))) end as ASR,
case when  SUM(cast(SuccessCalls as decimal(18,2)))  = 0  then 0.0 else (SUM(cast(TotalMins as decimal(18,2))) /  SUM(cast(SuccessCalls as decimal(18,2)))) end as ACD
from InterfaceMeraAdReport_CAV
where FromTime >= @timeFrom and ToTime <= @timeTo
 and Customer= @customer  and Area in ('62817','62818','62819','62859','62877','62878','62879') 
group by Customer

这个表每天增加大约300000条记录，所以现在上面的查询变得越来越慢，

我想创建索引以提高速度，但我不知道最有效的方法，任何人都可以告诉我哪些列将是最佳索引列

Answer 1

根据您的数据，您可能会发现FromTime > 20140128020000，尤其是ToTime < 20140128030000可能没有足够的选择性来保证单独使用这些列中的任何一个索引。

因此，您只需要Customer和Area - 您需要了解表格中这些列的数据分布情况。

假设Customer具有高选择性，并假设客户与区域高度相关（即客户通常只来自一个区域），那么请尝试尽可能缩小您的索引，例如：

CREATE INDEX IX_MyIndex ON InterfaceMeraAdReport_CAV(Customer)

如果客户与区域无关，或者客户本身不具有选择性：

CREATE INDEX IX_MyIndex ON InterfaceMeraAdReport_CAV(Customer, Area)

或者，如果Area的选择性高于客户：

CREATE INDEX IX_MyIndex ON InterfaceMeraAdReport_CAV(Area, Customer)

或者如果结果是报告仅针对最近的数据运行并且存在大量遗留数据，那么FromTime可能是有选择性的：

CREATE INDEX IX_MyIndex ON InterfaceMeraAdReport_CAV(FromTime, Customer)

等。即，您需要了解您的数据才能对索引做出决定。

由于您只获取了select中的6列，因此包含覆盖索引也是有意义的。

CREATE INDEX IX_MyIndex ON InterfaceMeraAdReport_CAV(Customer, Area) 
INCLUDE (Vendor, SuccessCalls, TotalCalls, TotalMins, Profix);

或者，如果这两个查询是针对此表的仅重要查询，那么您还应考虑根据这些查询选择CLUSTERED索引，例如优化最少的页面读取。 <{1}}，Customer和可能Area可能最适合。

（如果你把它作为聚集索引，显然你不需要覆盖索引。）

对于这个表，有一个最常用的查询，如何创建良好的索引来提高速度

1 个答案: