在项目中,我们经常遇到或用到分页,那么在大数据量(百万级以上)下,哪种分页算法效率最优呢?我们不妨用事实说话。
测试环境
硬件:CPU 酷睿双核T5750 内存:2G
软件:Windows server 2003 + Sql server 2005
OK,我们首先创建一数据库:data_Test,并在此数据库中创建一表:tb_TestTable
1
![]()
create database data_Test --创建数据库data_Test
2
![]()
GO
3
![]()
use data_Test
4
![]()
GO
5
![]()
create table tb_TestTable --创建表
6
![]()
(
7
![]()
id int identity(1,1) primary key,
8
![]()
userName nvarchar(20) not null,
9
![]()
userPWD nvarchar(20) not null,
10
![]()
userEmail nvarchar(40) null
11
![]()
)
12
![]()
GO
然后我们在数据表中插入2000000条数据:
1
![]()
--插入数据
2
![]()
set identity_insert tb_TestTable on
3
![]()
declare @count int
4
![]()
set @count=1
5
![]()
while @count<=2000000
6
![]()
begin
7
![]()
insert into tb_TestTable(id,userName,userPWD,userEmail) values(@count,'admin','admin888','lli0077@yahoo.com.cn')
8
![]()
set @count=@count+1
9
![]()
end
10
![]()
set identity_insert tb_TestTable off
我首先写了五个常用存储过程:
1,利用select top 和select not in进行分页,具体代码如下:
1
![]()
create procedure proc_paged_with_notin --利用select top and select not in
2
![]()
(
3
![]()
@pageIndex int, --页索引
4
![]()
@pageSize int --每页记录数
5
![]()
)
6
![]()
as
7
![]()
begin
8
![]()
set nocount on;
9
![]()
declare @timediff datetime --耗时
10
![]()
declare @sql nvarchar(500)
11
![]()
select @timediff=Getdate()
12
![]()
set @sql='select top '+str(@pageSize)+' * from tb_TestTable where(ID not in(select top '+str(@pageSize*@pageIndex)+' id from tb_TestTable order by ID ASC)) order by ID'
13
![]()
execute(@sql) --因select top后不支技直接接参数,所以写成了字符串@sql
14
![]()
select datediff(ms,@timediff,GetDate()) as 耗时
15
![]()
set nocount off;
16
![]()
end
2,利用select top 和 select max(列键)
1
![]()
create procedure proc_paged_with_selectMax --利用select top and select max(列)
2
![]()
(
3
![]()
@pageIndex int, --页索引
4
![]()
@pageSize int --页记录数
5
![]()
)
6
![]()
as
7
![]()
begin
8
![]()
set nocount on;
9
![]()
declare @timediff datetime
10
![]()
declare @sql nvarchar(500)
11
![]()
select @timediff=Getdate()
12
![]()
set @sql='select top '+str(@pageSize)+' * From tb_TestTable where(ID>(select max(id) From (select top '+str(@pageSize*@pageIndex)+' id From tb_TestTable order by ID) as TempTable)) order by ID'
13
![]()
execute(@sql)
14
![]()
select datediff(ms,@timediff,GetDate()) as 耗时
15
![]()
set nocount off;
16
![]()
end
3,利用select top和中间变量--此方法因网上有人说效果最佳,所以贴出来一同测试
1
![]()
create procedure proc_paged_with_Midvar --利用ID>最大ID值和中间变量
2
![]()
(
3
![]()
@pageIndex int,
4
![]()
@pageSize int
5
![]()
)
6
![]()
as
7
![]()
declare @count int
8
![]()
declare @ID int
9
![]()
declare @timediff datetime
10
![]()
declare @sql nvarchar(500)
11
![]()
begin
12
![]()
set nocount on;
13
![]()
select @count=0,@ID=0,@timediff=getdate()
14
![]()
select @count=@count+1,@ID=case when @count<=@pageSize*@pageIndex then ID else @ID end from tb_testTable order by id
15
![]()
set @sql='select top '+str(@pageSize)+' * from tb_testTable where ID>'+str(@ID)
16
![]()
execute(@sql)
17
![]()
select datediff(ms,@timediff,getdate()) as 耗时
18
![]()
set nocount off;
19
![]()
end
20
4,利用Row_number() 此方法为SQL server 2005中新的方法,利用Row_number()给数据行加上索引
1
![]()
create procedure proc_paged_with_Rownumber --利用SQL 2005中的Row_number()
2
![]()
(
3
![]()
@pageIndex int,
4
![]()
@pageSize int
5
![]()
)
6
![]()
as
7
![]()
declare @timediff datetime
8
![]()
begin
9
![]()
set nocount on;
10
![]()
select @timediff=getdate()
11
![]()
select * from (select *,Row_number() over(order by ID asc) as IDRank from tb_testTable) as IDWithRowNumber where IDRank>@pageSize*@pageIndex and IDRank<@pageSize*(@pageIndex+1)
12
![]()
select datediff(ms,@timediff,getdate()) as 耗时
13
![]()
set nocount off;
14
![]()
end
15
5,利用临时表及Row_number
1
![]()
create procedure proc_CTE --利用临时表及Row_number
2
![]()
(
3
![]()
@pageIndex int, --页索引
4
![]()
@pageSize int --页记录数
5
![]()
)
6
![]()
as
7
![]()
set nocount on;
8
![]()
declare @ctestr nvarchar(400)
9
![]()
declare @strSql nvarchar(400)
10
![]()
declare @datediff datetime
11
![]()
begin
12
![]()
select @datediff=GetDate()
13
![]()
set @ctestr='with Table_CTE as
14
![]()
(select ceiling((Row_number() over(order by ID ASC))/'+str(@pageSize)+') as page_num,* from tb_TestTable)';
15
![]()
set @strSql=@ctestr+' select * From Table_CTE where page_num='+str(@pageIndex)
16
![]()
end
17
![]()
begin
18
![]()
execute sp_executesql @strSql
19
![]()
select datediff(ms,@datediff,GetDate())
20
![]()
set nocount off;
21
![]()
end
22
OK,至此,存储过程创建完毕,我们分别在每页10条数据的情况下在第2页,第1000页,第10000页,第100000页,第199999页进行测试,耗时单位:ms 每页测试5次取其平均值
存过 |
第2页耗时 |
第1000页耗时 |
第10000页耗时 |
第100000页耗时 |
第199999页耗时 |
效率排行 |
1用not in |
0ms |
16ms |
47ms |
475ms |
953ms |
3 |
2用select max |
5ms |
16ms |
35ms |
325ms |
623ms |
1 |
3中间变量 |
966ms |
970ms |
960ms |
945ms |
933ms |
5 |
4row_number |
0ms |
0ms |
34ms |
365ms |
710ms |
2 |
4临时表 |
780ms |
796ms |
798ms |
780ms |
805ms |
4 |
测试结果显示:select max >row_number>not in>临时表>中间变量
于是我对效率最高的select max方法用2分法进行了扩展,代码取自互联网,我修改了ASC排序时取不到值的BUG,测试结果:
2分法 |
156ms |
156ms |
180ms |
470ms |
156ms |
1* |
从测试结果来看,使用2分法确实可以提高效率并使效率更为稳定,我又增加了第159999页的测试,用时仅296ms,效果相当的不错!
下面是2分法使用select max的代码,已相当完善。
1
![]()
--/*-----存储过程 分页处理 孙伟 2005-03-28创建 -------*/
2
![]()
--/*-----存储过程 分页处理 浪尘 2008-9-1修改----------*/
3
![]()
--/*----- 对数据进行了2分处理使查询前半部分数据与查询后半部分数据性能相同 -------*/
4
![]()
5
![]()
alter PROCEDURE proc_paged_2part_selectMax
6
![]()
(
7
![]()
@tblName nvarchar(200), ----要显示的表或多个表的连接
8
![]()
@fldName nvarchar(500) = '*', ----要显示的字段列表
9
![]()
@pageSize int = 10, ----每页显示的记录个数
10
![]()
@page int = 1, ----要显示那一页的记录
11
![]()
@fldSort nvarchar(200) = null, ----排序字段列表或条件
12
![]()
@Sort bit = 0, ----排序方法,0为升序,1为降序(如果是多字段排列Sort指代最后一个排序字段的排列顺序(最后一个排序字段不加排序标记)--程序传参如:' SortA Asc,SortB Desc,SortC ')
13
![]()
@strCondition nvarchar(1000) = null, ----查询条件,不需where
14
![]()
@ID nvarchar(150), ----主表的主键
15
![]()
@Dist bit = 0, ----是否添加查询字段的 DISTINCT 默认0不添加/1添加
16
![]()
@pageCount int = 1 output, ----查询结果分页后的总页数
17
![]()
@Counts int = 1 output ----查询到的记录数
18
![]()
)
19
![]()
AS
20
![]()
SET NOCOUNT ON
21
![]()
Declare @sqlTmp nvarchar(1000) ----存放动态生成的SQL语句
22
![]()
Declare @strTmp nvarchar(1000) ----存放取得查询结果总数的查询语句
23
![]()
Declare @strID nvarchar(1000) ----存放取得查询开头或结尾ID的查询语句
24
![]()
25
![]()
Declare @strSortType nvarchar(10) ----数据排序规则A
26
![]()
Declare @strFSortType nvarchar(10) ----数据排序规则B
27
![]()
28
![]()
Declare @SqlSelect nvarchar(50) ----对含有DISTINCT的查询进行SQL构造
29
![]()
Declare @SqlCounts nvarchar(50) ----对含有DISTINCT的总数查询进行SQL构造
30
![]()
31
![]()
declare @timediff datetime --耗时测试时间差
32
![]()
select @timediff=getdate()
33
![]()
34
![]()
if @Dist = 0
35
![]()
begin
36
![]()
set @SqlSelect = 'select '
37
![]()
set @SqlCounts = 'Count(*)'
38
![]()
end
39
![]()
else
40
![]()
begin
41
![]()
set @SqlSelect = 'select distinct '
42
![]()
set @SqlCounts = 'Count(DISTINCT '+@ID+')'
43
![]()
end
44
![]()
45
![]()
46
![]()
if @Sort=0
47
![]()
begin
48
![]()
set @strFSortType=' ASC '
49
![]()
set @strSortType=' DESC '
50
![]()
end
51
![]()
else
52
![]()
begin
53
![]()
set @strFSortType=' DESC '
54
![]()
set @strSortType=' ASC '
55
![]()
end
56
![]()
57
![]()
58
![]()
59
![]()
--------生成查询语句--------
60
![]()
--此处@strTmp为取得查询结果数量的语句
61
![]()
if @strCondition is null or @strCondition='' --没有设置显示条件
62
![]()
begin
63
![]()
set @sqlTmp = @fldName + ' From ' + @tblName
64
![]()
set @strTmp = @SqlSelect+' @Counts='+@SqlCounts+' FROM '+@tblName
65
![]()
set @strID = ' From ' + @tblName
66
![]()
end
67
![]()
else
68
![]()
begin
69
![]()
set @sqlTmp = + @fldName + 'From ' + @tblName + ' where (1>0) ' + @strCondition
70
![]()
set @strTmp = @SqlSelect+' @Counts='+@SqlCounts+' FROM '+@tblName + ' where (1>0) ' + @strCondition
71
![]()
set @strID = ' From ' + @tblName + ' where (1>0) ' + @strCondition
72
![]()
end
73
![]()
74
![]()
----取得查询结果总数量-----
75
![]()
exec sp_executesql @strTmp,N'@Counts int out ',@Counts out
76
![]()
declare @tmpCounts int
77
![]()
if @Counts = 0
78
![]()
set @tmpCounts = 1
79
![]()
else
80
![]()
set @tmpCounts = @Counts
81
![]()
82
![]()
--取得分页总数
83
![]()
set @pageCount=(@tmpCounts+@pageSize-1)/@pageSize
84
![]()
85
/**//**当前页大于总页数 取最后一页**/
86
if @page>@pageCount
87
set @page=@pageCount
88![]()
89
--/*-----数据分页2分处理-------*/
90
declare @pageIndex int --总数/页大小
91
declare @lastcount int --总数%页大小
92![]()
93
set @pageIndex = @tmpCounts/@pageSize
94
set @lastcount = @tmpCounts%@pageSize
95
if @lastcount > 0
96
set @pageIndex = @pageIndex + 1
97
else
98
set @lastcount = @pagesize
99![]()
100
--//***显示分页
101
if @strCondition is null or @strCondition='' --没有设置显示条件
102
begin
103
if @pageIndex<2 or @page<=@pageIndex / 2 + @pageIndex % 2 --前半部分数据处理
104
begin
105
if @page=1
106
set @strTmp=@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName
107
+' order by '+ @fldSort +' '+ @strFSortType
108
else
109
begin
110
if @Sort=1
111
begin
112
set @strTmp=@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName
113
+' where '+@ID+' <(select min('+ @ID +') from ('+ @SqlSelect+' top '+ CAST(@pageSize*(@page-1) as Varchar(20)) +' '+ @ID +' from '+@tblName
114
+' order by '+ @fldSort +' '+ @strFSortType+') AS TBMinID)'
115
+' order by '+ @fldSort +' '+ @strFSortType
116
end
117
else
118
begin
119
set @strTmp=@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName
120
+' where '+@ID+' >(select max('+ @ID +') from ('+ @SqlSelect+' top '+ CAST(@pageSize*(@page-1) as Varchar(20)) +' '+ @ID +' from '+@tblName
121
+' order by '+ @fldSort +' '+ @strFSortType+') AS TBMinID)'
122
+' order by '+ @fldSort +' '+ @strFSortType
123
end
124
end
125
end
126
else
127
begin
128
set @page = @pageIndex-@page+1 --后半部分数据处理
129
if @page <= 1 --最后一页数据显示
130
set @strTmp=@SqlSelect+' * from ('+@SqlSelect+' top '+ CAST(@lastcount as VARCHAR(4))+' '+ @fldName+' from '+@tblName
131
+' order by '+ @fldSort +' '+ @strSortType+') AS TempTB'+' order by '+ @fldSort +' '+ @strFSortType
132
else
133
if @Sort=1
134
begin
135
set @strTmp=@SqlSelect+' * from ('+@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName
136
+' where '+@ID+' >(select max('+ @ID +') from('+ @SqlSelect+' top '+ CAST(@pageSize*(@page-2)+@lastcount as Varchar(20)) +' '+ @ID +' from '+@tblName
137
+' order by '+ @fldSort +' '+ @strSortType+') AS TBMaxID)'
138
+' order by '+ @fldSort +' '+ @strSortType+') AS TempTB'+' order by '+ @fldSort +' '+ @strFSortType
139
end
140
else
141
begin
142
set @strTmp=@SqlSelect+' * from ('+@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName
143
+' where '+@ID+' <(select min('+ @ID +') from('+ @SqlSelect+' top '+ CAST(@pageSize*(@page-2)+@lastcount as Varchar(20)) +' '+ @ID +' from '+@tblName
144
+' order by '+ @fldSort +' '+ @strSortType+') AS TBMaxID)'
145
+' order by '+ @fldSort +' '+ @strSortType+') AS TempTB'+' order by '+ @fldSort +' '+ @strFSortType
146
end
147
end
148
end
149![]()
150
else --有查询条件
151
begin
152
if @pageIndex<2 or @page<=@pageIndex / 2 + @pageIndex % 2 --前半部分数据处理
153
begin
154
if @page=1
155
set @strTmp=@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName
156
+' where 1=1 ' + @strCondition + ' order by '+ @fldSort +' '+ @strFSortType
157
else if(@Sort=1)
158
begin
159
set @strTmp=@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName
160
+' where '+@ID+' <(select min('+ @ID +') from ('+ @SqlSelect+' top '+ CAST(@pageSize*(@page-1) as Varchar(20)) +' '+ @ID +' from '+@tblName
161
+' where (1=1) ' + @strCondition +' order by '+ @fldSort +' '+ @strFSortType+') AS TBMinID)'
162
+' '+ @strCondition +' order by '+ @fldSort +' '+ @strFSortType
163
end
164
else
165
begin
166
set @strTmp=@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName
167
+' where '+@ID+' >(select max('+ @ID +') from ('+ @SqlSelect+' top '+ CAST(@pageSize*(@page-1) as Varchar(20)) +' '+ @ID +' from '+@tblName
168
+' where (1=1) ' + @strCondition +' order by '+ @fldSort +' '+ @strFSortType+') AS TBMinID)'
169
+' '+ @strCondition +' order by '+ @fldSort +' '+ @strFSortType
170
end
171
end
172
else
173
begin
174
set @page = @pageIndex-@page+1 --后半部分数据处理
175
if @page <= 1 --最后一页数据显示
176
set @strTmp=@SqlSelect+' * from ('+@SqlSelect+' top '+ CAST(@lastcount as VARCHAR(4))+' '+ @fldName+' from '+@tblName
177
+' where (1=1) '+ @strCondition +' order by '+ @fldSort +' '+ @strSortType+') AS TempTB'+' order by '+ @fldSort +' '+ @strFSortType
178
else if(@Sort=1)
179
set @strTmp=@SqlSelect+' * from ('+@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName
180
+' where '+@ID+' >(select max('+ @ID +') from('+ @SqlSelect+' top '+ CAST(@pageSize*(@page-2)+@lastcount as Varchar(20)) +' '+ @ID +' from '+@tblName
181
+' where (1=1) '+ @strCondition +' order by '+ @fldSort +' '+ @strSortType+') AS TBMaxID)'
182
+' '+ @strCondition+' order by '+ @fldSort +' '+ @strSortType+') AS TempTB'+' order by '+ @fldSort +' '+ @strFSortType
183
else
184
set @strTmp=@SqlSelect+' * from ('+@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName
185
+' where '+@ID+' <(select min('+ @ID +') from('+ @SqlSelect+' top '+ CAST(@pageSize*(@page-2)+@lastcount as Varchar(20)) +' '+ @ID +' from '+@tblName
186
+' where (1=1) '+ @strCondition +' order by '+ @fldSort +' '+ @strSortType+') AS TBMaxID)'
187
+' '+ @strCondition+' order by '+ @fldSort +' '+ @strSortType+') AS TempTB'+' order by '+ @fldSort +' '+ @strFSortType
188
end
189
end
190![]()
191
------返回查询结果-----
192
exec sp_executesql @strTmp
193
select datediff(ms,@timediff,getdate()) as 耗时
194
--print @strTmp
195
SET NOCOUNT OFF
196
GO
197
![复制代码]()