最近在忙着优化集团公司的一个报表。优化完成后，报表查询速度有从半小时以上(甚至查不出)到秒查的质变。从修改SQL查询语句逻辑到决定创建存储

过程实现，花了我3天多的时间，在此总结一下，希望对朋友们有帮助。

数据背景

首先项目是西门子中国在我司实施部署的MES项目，由于项目是在产线上运作(3 years+)，数据累积很大。在项目的数据库中，大概上亿条数据的表有5个以上，千万级数据的表10个以上，百万级数据的表，很多...

(历史问题，当初实施无人监管，无人监控数据库这块的性能问题。ps:我刚入职不久...)

不多说，直接贴西门子中国的开发人员在我司开发的SSRS报表中的SQL语句：

 1 select distinct b.MaterialID as matl_def_id, c.Descript, case when right(b.MESOrderID, 12) < '001000000000' then right(b.MESOrderID, 9)
 2 else right(b.MESOrderID, 12) end  as pom_order_id, a.LotName, a.SourceLotName as ComLot,
 3 e.DefID as ComMaterials, e.Descript as ComMatDes, d.VendorID, d.DateCode,d.SNNote, b.OnPlantID,a.SNCUST
 4 from
 5 (
 6     select m.lotname, m.sourcelotname, m.opetypeid, m.OperationDate,n.SNCUST from View1 m
 7     left join co_sn_link_customer as n on n.SNMes=m.LotName
 8     where
 9     ( m.LotName in (select val from fn_String_To_Table(@sn,',',1)) or (@sn) = '') and
10     ( m.sourcelotname in (select val from fn_String_To_Table(@BatchID,',',1)) or (@BatchID) = '')
11     and (n.SNCust like '%'+ @SN_ext + '%' or (@SN_ext)='')
12 ) a
13 left join
14 (
15     select * from Table1 where SNType = 'IntSN'
16     and SNRuleName = 'ProductSNRule'
17     and OnPlantID=@OnPlant
18 ) b on b.SN = a.LotName
19 inner join MMdefinitions as c on c.DefID = b.MaterialID
20 left join  Table1 as d on d.SN = a.SourceLotName
21 inner join MMDefinitions as e on e.DefID = d.MaterialID
22 where not exists (
23  select distinct LotName, SourceLotName from ELCV_ASSEMBLE_OPS
24 where LotName = a.SourceLotName and SourceLotName = a.LotName
25 )
26 and (d.DateCode in (select val from fn_String_To_Table(@DCode,',',1)) or (@DCode) = '')
27 and (d.SNNote  like '%'+@SNNote+'%' or (@SNNote) = '')
28 and ((case when right(b.MESOrderID, 12) < '001000000000' then right(b.MESOrderID, 9)
29 else right(b.MESOrderID, 12) end) in (select val from fn_String_To_Table(@order_id,',',1)) or (@order_id) = '')
30 and (e.DefID in (select val from fn_String_To_Table(@comdef,',',1)) or (@comdef) = '')
31 --View1是一个嵌套两层的视图(出于保密性，实际名称可能不同)，里面有一张上亿数据的表和几张千万级数据的表做左连接查询
32 --Table1是一个数据记录超过1500万的表

View Code

这个查询语句，实际上通过我的检测和调查，在B/S系统前端已无法查出结果，半小时，一小时 ... 。因为我直接在SQL查询分析器查，半小时都没有结果。

(原因是里面对一张上亿级数据表和3张千万级数据表做全表扫描查询)

不由感慨，西门子中国的素质(或者说责任感)就这样？

下面说说我的分析和走的弯路(思维误区)，希望对你也有警醒。

探索和误区

首先相关表的索引，没有建全的，把索引给建上。

索引这步完成后，发现情况还是一样，查询速度几乎没有改善。后来想起相关千万级数据以上的表，都还没有建立表分区。于是考虑建立表分区以及数据复制的方案。

这里有必要说明下：我司报表用的是一个专门的数据库服务器，数据从产线订阅而来。就是常说的“读写分离”。

如果直接在原表上建立表分区，你会发现执行表分区的事物会直接死锁。原因是：表分区操作本身会锁表，产线还在推数据过来，这样很容易“阻塞”，“死锁”。

我想好的方案是：建立一个新表(空表)，在新表上建好表分区，然后复制数据过来。

正打算这么干。等等！我好像进入了一个严重的误区！

分析： 原SQL语句和业务需求，是对产线的数据做产品以及序列号的追溯，关键是查询条件里没有有规律的"条件"(如日期、编号)，

         贸然做了表分区，在这里几乎没有意义！反而会降低查询性能！

好险！还是一步一步来，先做SQL语句分析。

一. 对原SQL语句的分析

1. 查询语句的where条件，有大量@var in ... or (@var ='') 的片段

2. where条件有like '%'+@var+'%'

3. where条件有 case ... end 函数

4. 多次连接同一表查询，另外使用本身已嵌套的视图表，是不是必须，是否可替代？

5. SQL语句有*号，视图中也有*号出现

二. 优化设计

首先是用存储过程改写，好处是设计灵活。

核心思想是：用一个或多个查询条件(查询条件要求至少输入一个)得到临时表，每个查询条件如果查到集合，就更新这张临时表，最后汇总的时候，

                 只需判断这个临时表是否有值。以此类推，可以建立多个临时表，将查询条件汇总。

这样做目前来看至少两点好处：1.省去了对变量进行 =@var or (@var='')的判断；

                                        2.抛弃sql拼接，提高代码可读性。

再有就是在书写存储过程，这个过程中要注意：

1. 尽量想办法使用临时表扫描替代全表扫描；

2. 抛弃in和not in语句，使用exists和not exists替代；

3. 和客户确认，模糊查询是否有必要，如没有必要，去掉like语句；

4. 注意建立适当的，符合场景的索引；

5. 踩死 "*" 号；

6. 避免在where条件中对字段进行函数操作；

7. 对实时性要求不高的报表，允许脏读(with(nolock))。

三. 存储过程

如果想参考优化设计片段的详细内容，请参阅SQL代码：

  1 /**
  2  * 某某跟踪报表
  3  **/
  4 --exec spName1 '','','','','','','公司代号'
  5 CREATE Procedure spName1
  6    @MESOrderID nvarchar(320), --工单号,最多30个
  7    @LotName nvarchar(700),    --产品序列号,最多50个
  8    @DateCode nvarchar(500),   --供应商批次号,最多30个
  9    @BatchID nvarchar(700),    --组装件序列号/物料批号,最多50个
 10    @comdef nvarchar(700),     --组装件物料编码,最多30个
 11    @SNCust nvarchar(1600),    --外部序列号,最多50个
 12    @OnPlant nvarchar(20)      --平台
 13 AS
 14 BEGIN
 15     SET NOCOUNT ON;
 16     /**
 17      * 1)定义全局的临时表，先根据六个查询条件的任意一个，得出临时表结果
 18      **/
 19     CREATE TABLE #FinalLotName
 20     (
 21         LotName NVARCHAR(50),       --序列号
 22         SourceLotName NVARCHAR(50), --来源序列号
 23         SNCust NVARCHAR(128)        --外部序列号
 24     )
 25     --1.1
 26     IF @LotName<>''
 27     BEGIN
 28         SELECT Val INTO #WorkLot FROM fn_String_To_Table(@LotName,',',1)
 29         SELECT LotPK,LotName INTO #WorkLotPK FROM MMLots WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkLot b WHERE b.Val=MMLots.LotID)
 30
 31         --求SourceLotPK只能在这里求
 32         SELECT a.LotPK,a.SourceLotPK into #WorkSourcePK FROM MMLotOperations a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkLotPK b WHERE b.LotPK=a.LotPK) AND a.SourceLotPK IS NOT NULL
 33
 34         SELECT a.LotPK,a.SourceLotPK,b.LotName INTO #WorkSourcePK2 FROM #WorkSourcePK a JOIN #WorkLotPK b ON a.LotPK=b.LotPK
 35
 36         INSERT INTO #FinalLotName SELECT a.LotName,b.LotName AS SourceLotName,NULL FROM #WorkSourcePK2 a JOIN (SELECT LotPK,LotName FROM MMLots WITH(NOLOCK) ) b on a.SourceLotPK=b.LotPK --b的里面加不加WHERE RowDeleted=0待确定
 37         SELECT a.LotName,a.SourceLotName,b.SNCust INTO #FinalLotNameX1 FROM #FinalLotName a LEFT JOIN CO_SN_LINK_CUSTOMER b WITH(NOLOCK) ON a.LotName=b.SNMes
 38         DELETE FROM #FinalLotName
 39         INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #FinalLotNameX1
 40     END
 41     --1.2
 42     IF @BatchID<>''
 43     BEGIN
 44         SELECT Val INTO #WorkSourceLot FROM fn_String_To_Table(@BatchID,',',1)
 45         IF EXISTS(SELECT 1 FROM #FinalLotName)--如果@LotName也不为空
 46         BEGIN
 47             SELECT a.LotName,a.SourceLotName,a.SNCust INTO #FinalLotNameX2 FROM #FinalLotName a WHERE EXISTS(SELECT 1 FROM #WorkSourceLot b WHERE a.SourceLotName=b.Val)
 48             DELETE FROM #FinalLotName
 49             INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #FinalLotNameX2
 50         END
 51         ELSE --@LotName条件为空
 52         BEGIN
 53             SELECT LotPK AS SourceLotPK,LotName AS SourceLotName INTO #2 FROM MMLots WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkSourceLot b WHERE b.Val=MMLots.LotID)
 54             SELECT a.LotPK,a.SourceLotPK into #21 FROM MMLotOperations a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #2 b WHERE b.SourceLotPK=a.SourceLotPK)
 55             SELECT a.LotPK,a.SourceLotPK,b.SourceLotName INTO #22 FROM #21 a JOIN #2 b ON a.SourceLotPK=b.SourceLotPK
 56             INSERT INTO #FinalLotName SELECT b.LotName,a.SourceLotName,NULL FROM #22 a JOIN (SELECT LotPK,LotName FROM MMLots WITH(NOLOCK) ) b on a.LotPK=b.LotPK --b的里面加不加WHERE RowDeleted=0待确定
 57             SELECT a.LotName,a.SourceLotName,b.SNCust INTO #FinalLotNameX21 FROM #FinalLotName a LEFT JOIN CO_SN_LINK_CUSTOMER b WITH(NOLOCK) ON a.LotName=b.SNMes
 58             DELETE FROM #FinalLotName
 59             INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #FinalLotNameX21
 60         END
 61     END
 62     --1.3
 63     IF @SNCust<>''
 64     BEGIN
 65         SELECT Val INTO #WorkCustomSN FROM fn_String_To_Table(@SNCust,',',1)
 66         IF EXISTS(SELECT 1 FROM #FinalLotName)--前面两个条件至少有一个有值
 67         BEGIN
 68             SELECT a.LotName,a.SourceLotName,a.SNCust INTO #FinalLotNameX3 FROM #FinalLotName a WHERE EXISTS(SELECT 1 FROM #WorkCustomSN b WHERE a.SNCust=b.Val)
 69             DELETE FROM #FinalLotName
 70             INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #FinalLotNameX3
 71         END
 72         ELSE
 73         BEGIN
 74             SELECT a.SNMes INTO #WorkLotX FROM CO_SN_LINK_CUSTOMER a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkCustomSN b WHERE a.SNCust=b.Val)
 75             -------------------以下逻辑和变量1(@LotName)类似[先根据外部序列号求解序列号,再照搬第一个判断变量的方式]
 76             SELECT LotPK,LotName INTO #WorkLotPKX FROM MMLots WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkLotX b WHERE b.SNMes=MMLots.LotID)
 77
 78             --求SourceLotPK只能在这里求
 79             SELECT a.LotPK,a.SourceLotPK into #WorkSourcePKX FROM MMLotOperations a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkLotPKX b WHERE b.LotPK=a.LotPK) AND a.SourceLotPK IS NOT NULL
 80
 81             SELECT a.LotPK,a.SourceLotPK,b.LotName INTO #WorkSourcePK2X FROM #WorkSourcePKX a JOIN #WorkLotPKX b ON a.LotPK=b.LotPK
 82
 83             INSERT INTO #FinalLotName SELECT a.LotName,b.LotName AS SourceLotName,NULL FROM #WorkSourcePK2X a JOIN (SELECT LotPK,LotName FROM MMLots WITH(NOLOCK) ) b on a.SourceLotPK=b.LotPK --b的里面加不加WHERE RowDeleted=0待确定
 84             SELECT a.LotName,a.SourceLotName,b.SNCust INTO #FinalLotNameX31 FROM #FinalLotName a LEFT JOIN CO_SN_LINK_CUSTOMER b WITH(NOLOCK) ON a.LotName=b.SNMes
 85             DELETE FROM #FinalLotName
 86             INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #FinalLotNameX31
 87             -----------------------
 88         END
 89     END
 90
 91     /**
 92      * 2)定义全局的临时表，用于替换第一个全局临时表。
 93      **/
 94     CREATE TABLE #FinalCO_SN
 95     (
 96         SN NVARCHAR(50),
 97         SourceSN NVARCHAR(50),
 98         SNCust NVARCHAR(128),
 99         matl_def_id NVARCHAR(50),--sn的物料ID
100         ComMaterials NVARCHAR(50),  --SourceSN的物料ID
101         MESOrderID NVARCHAR(20),
102         OnPlantID NVARCHAR(20),
103         VendorID NVARCHAR(20),
104         DateCode NVARCHAR(20) ,
105         SNNote NVARCHAR(512)
106     )
107     --2.1
108     IF @MESOrderID<>''
109     BEGIN
110         -------------------------------将MESOrderID做特殊处理-----------------------------------
111         SELECT Val INTO #WorkMESOrderID FROM fn_String_To_Table(@MESOrderID,',',1)
112         IF @OnPlant='Comba'
113         BEGIN
114             UPDATE #WorkMESOrderID SET Val='C000'+Val WHERE LEN(Val)=9
115         END
116         ELSE
117         BEGIN
118             UPDATE #WorkMESOrderID SET Val='W000'+Val WHERE LEN(Val)=9
119         END
120         SELECT SN,MaterialID,MESOrderID,OnPlantID INTO #WorkCO_SN1 FROM CO_SN_GENERATION a WITH(NOLOCK)
121         WHERE SNType='IntSN' AND SNRuleName = 'ProductSNRule' AND OnPlantID=@OnPlant
122         AND EXISTS(SELECT 1 FROM #WorkMESOrderID b WHERE a.MESOrderID=b.Val)
123         ------------------------------------------------------------------------------------------
124         --条件判断(逻辑分析)开始
125         IF EXISTS(SELECT 1 FROM #FinalLotName)--如果前面判断的查询条件有值
126         BEGIN
127             --查出SourceLotName对应的查询字段

128             SELECT a.SN AS SourceLotName,a.VendorID,a.DateCode,a.SNNote,a.MaterialID AS ComMaterials INTO #SourceLotNameTable FROM CO_SN_GENERATION a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SN=b.SourceLotName)
129
130             INSERT INTO #FinalCO_SN
131             SELECT a.LotName,a.SourceLotName,d.SNCust,b.MaterialID,c.ComMaterials,b.MESOrderID,b.OnPlantID,c.VendorID,c.DateCode,c.SNNote FROM #FinalLotName a
132             LEFT JOIN #WorkCO_SN1 b ON a.LotName=b.SN
133             LEFT JOIN #SourceLotNameTable c ON a.SourceLotName=c.SourceLotName
134             LEFT JOIN CO_SN_LINK_CUSTOMER d WITH(NOLOCK) ON a.LotName=d.SNMes
135         END
136         ELSE
137         BEGIN
138             --已知SN集合求解对应的SourceSN和SNCust集合------------------------------------------
139             SELECT LotPK,LotName INTO #WorkLotPK410 FROM MMLots WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkCO_SN1 b WHERE b.SN=MMLots.LotID)
140             SELECT a.LotPK,a.SourceLotPK into #WorkSourcePK420 FROM MMLotOperations a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkLotPK410 b WHERE b.LotPK=a.LotPK) AND a.SourceLotPK IS NOT NULL
141             SELECT a.LotPK,a.SourceLotPK,b.LotName INTO #WorkSourcePK430 FROM #WorkSourcePK420 a JOIN #WorkLotPK410 b ON a.LotPK=b.LotPK
142             INSERT INTO #FinalLotName SELECT a.LotName,b.LotName AS SourceLotName,NULL FROM #WorkSourcePK430 a JOIN (SELECT LotPK,LotName FROM MMLots WITH(NOLOCK) ) b on a.SourceLotPK=b.LotPK --b的里面加不加WHERE RowDeleted=0待确定
143
144             SELECT a.LotName,a.SourceLotName,b.SNCust INTO #FinalLotNameX440 FROM #FinalLotName a LEFT JOIN CO_SN_LINK_CUSTOMER b WITH(NOLOCK) ON a.LotName=b.SNMes
145             DELETE FROM #FinalLotName
146             INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #FinalLotNameX440
147             -------------------------------------------------------------------------------------
148             SELECT a.SN AS SourceLotName,a.VendorID,a.DateCode,a.SNNote,a.MaterialID AS ComMaterials INTO #SourceLotNameTable2 FROM CO_SN_GENERATION a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SN=b.SourceLotName)
149
150             INSERT INTO #FinalCO_SN
151             SELECT a.LotName,a.SourceLotName,a.SNCust,b.MaterialID,c.ComMaterials,b.MESOrderID,b.OnPlantID,c.VendorID,c.DateCode,c.SNNote FROM #FinalLotName a
152             LEFT JOIN #WorkCO_SN1 b ON a.LotName=b.SN
153             LEFT JOIN #SourceLotNameTable2 c ON a.SourceLotName=c.SourceLotName
154         END
155     END
156     --2.2
157     IF @DateCode<>''
158     BEGIN
159         SELECT Val INTO #WorkDateCode FROM fn_String_To_Table(@DateCode,',',1)
160         --此@DataCode条件求解出来的是SourceSN
161         SELECT SN AS SourceSN,MaterialID AS ComMaterials,VendorID,DateCode,SNNote INTO #WorkSourceSNT1 FROM CO_SN_GENERATION a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkDateCode b WHERE a.DateCode=b.Val)
162         ----------------------------------------------------------------------------------------------------
163         --条件判断(逻辑分析)开始
164         IF EXISTS(SELECT 1 FROM #FinalCO_SN)--如果前面判断的查询条件有值
165         BEGIN
166             SELECT a.LotName,a.SourceLotName,a.SNCust,a.MaterialID,a.ComMaterials,a.MESOrderID,a.OnPlantID,a.VendorID,a.DateCode,a.SNNote INTO #TMP51 FROM #FinalCO_SN a WHERE EXISTS (SELECT 1 FROM #WorkDateCode b WHERE a.DateCode=b.Val)
167             DELETE FROM #FinalCO_SN
168             INSERT INTO #FinalCO_SN SELECT LotName,SourceLotName,SNCust,MaterialID,ComMaterials,MESOrderID,OnPlantID,VendorID,DateCode,SNNote FROM #TMP51
169         END
170         ELSE
171         BEGIN
172             IF EXISTS(SELECT 1 FROM #FinalLotName)
173             BEGIN
174             --查出SourceLotName对应的查询字段
175             SELECT a.SourceSN,a.VendorID,a.DateCode,a.SNNote,a.ComMaterials INTO #SourceLTX5 FROM #WorkSourceSNT1 a WHERE EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SourceSN=b.SourceLotName)
176             --查出SN对应的查询字段
177             SELECT SN,MaterialID,MESOrderID,OnPlantID INTO #WorkSNT510 FROM CO_SN_GENERATION a WITH(NOLOCK)
178             WHERE SNType='IntSN' AND SNRuleName = 'ProductSNRule' AND OnPlantID=@OnPlant
179             AND EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SN=b.LotName)
180
181             INSERT INTO #FinalCO_SN
182             SELECT a.LotName,a.SourceLotName,d.SNCust,b.MaterialID,c.ComMaterials,b.MESOrderID,b.OnPlantID,c.VendorID,c.DateCode,c.SNNote FROM #FinalLotName a
183             LEFT JOIN #WorkSNT510 b ON a.LotName=b.SN
184             LEFT JOIN #WorkSourceSNT1 c ON a.SourceLotName=c.SourceSN
185             LEFT JOIN CO_SN_LINK_CUSTOMER d WITH(NOLOCK) ON a.LotName=d.SNMes
186
187             END
188             ELSE
189             BEGIN
190                 --已知SourceSN集合求解对应的SN和SNCust集合------------------------------------------