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
create database data_Test --创建数据库data_TestGOuse data_TestGOcreate table tb_TestTable --创建表(id int identity(1,1) primary key,userName nvarchar(20) not null,userPWD nvarchar(20) not null,userEmail nvarchar(40) null)GO
然后我们在数据表中插入2000000条数据:
--插入数据set identity_insert tb_TestTable ondeclare @count intset @count=1while @count<=2000000begininsert into tb_TestTable(id,userName,userPWD,userEmail) values(@count,'admin','admin888','lli0077@yahoo.com.cn')set @count=@count+1endset 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：
create procedure proc_paged_with_notin --利用select top and select not in(@pageIndex int, --页索引 @pageSize int --每页记录数)asbeginset nocount on;declare @timediff datetime --耗时 declare @sql nvarchar(500)select @timediff=Getdate()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'execute(@sql) --因select top后不支技直接接参数，所以写成了字符串@sql select datediff(ms,@timediff,GetDate()) as 耗时set nocount off;end
2,利用select top 和 select max(列键)
create procedure proc_paged_with_selectMax --利用select top and select max(列)(@pageIndex int, --页索引 @pageSize int --页记录数)asbeginset nocount on;declare @timediff datetimedeclare @sql nvarchar(500)select @timediff=Getdate()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'execute(@sql)select datediff(ms,@timediff,GetDate()) as 耗时set nocount off;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
create procedure proc_paged_with_Midvar --利用ID>最大ID值和中间变量(@pageIndex int,@pageSize int)asdeclare @count intdeclare @ID intdeclare @timediff datetimedeclare @sql nvarchar(500)beginset nocount on;select @count=0,@ID=0,@timediff=getdate()select @count=@count+1,@ID=case when @count<=@pageSize*@pageIndex then ID
else @ID end from tb_testTable order by idset @sql='select top '+str(@pageSize)+' * from tb_testTable where ID>'+str(@ID)execute(@sql)select datediff(ms,@timediff,getdate()) as 耗时set nocount off;end
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
create procedure proc_paged_with_Rownumber --利用SQL 2005中的Row_number()(@pageIndex int,@pageSize int)asdeclare @timediff datetimebeginset nocount on;select @timediff=getdate()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)select datediff(ms,@timediff,getdate()) as 耗时set nocount off;end
5，利用临时表及Row_number
create procedure proc_CTE --利用临时表及Row_number(@pageIndex int, --页索引 @pageSize int --页记录数)asset nocount on;declare @ctestr nvarchar(400)declare @strSql nvarchar(400)declare @datediff datetimebeginselect @datediff=GetDate()set @ctestr='with Table_CTE as(select ceiling((Row_number() over(order by ID ASC))/'+str(@pageSize)+')
as page_num,* from tb_TestTable)';set @strSql=@ctestr+' select * From Table_CTE where page_num='+str(@pageIndex)endbeginexecute sp_executesql @strSqlselect datediff(ms,@datediff,GetDate())set nocount off;end
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 | 第10000页 | 第100000页 | 第199999页 | 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 |
| 5临时表 | 780ms | 796ms | 798ms | 780ms | 805ms | 4 |
测试结果显示：
| 输出窗口 | 复制 保存 |
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:
| 存过 | 第2页耗时 | 第1000页 | 第10000页 | 第100000页 | 第199999页 | 效率排行 |
| 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。
--/*-----存储过程 分页处理 孙伟 2005-03-28创建 -------*/--/*-----存储过程 分页处理 浪尘 2008-9-1修改----------*/--/*----- 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 -------*/alter PROCEDURE proc_paged_2part_selectMax(@tblName nvarchar(200), ----要显示的表或多个表的连接@fldName nvarchar(500) = '*', ----要显示的字段列表@pageSize int = 10, ----每页显示的记录个数@page int = 1, ----要显示那一页的记录@fldSort nvarchar(200) = null, ----排序字段列表或条件@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 ')@strCondition nvarchar(1000) = null, ----查询条件,不需where@ID nvarchar(150), ----主表的主键@Dist bit = 0, ----是否添加查询字段的 DISTINCT 默认0不添加/1添加@pageCount int = 1 output, ----查询结果分页后的总页数@Counts int = 1 output ----查询到的记录数)ASSET NOCOUNT ONDeclare @sqlTmp nvarchar(1000) ----存放动态生成的SQL语句Declare @strTmp nvarchar(1000) ----存放取得查询结果总数的查询语句Declare @strID nvarchar(1000) ----存放取得查询开头或结尾ID的查询语句Declare @strSortType nvarchar(10) ----数据排序规则ADeclare @strFSortType nvarchar(10) ----数据排序规则BDeclare @SqlSelect nvarchar(50) ----对含有DISTINCT的查询进行SQL构造Declare @SqlCounts nvarchar(50) ----对含有DISTINCT的总数查询进行SQL构造declare @timediff datetime --耗时测试时间差select @timediff=getdate()if @Dist = 0beginset @SqlSelect = 'select 'set @SqlCounts = 'Count(*)'endelsebeginset @SqlSelect = 'select distinct 'set @SqlCounts = 'Count(DISTINCT '+@ID+')'endif @Sort=0beginset @strFSortType=' ASC 'set @strSortType=' DESC 'endelsebeginset @strFSortType=' DESC 'set @strSortType=' ASC 'end--------生成查询语句----------此处@strTmp为取得查询结果数量的语句if @strCondition is null or @strCondition='' --没有设置显示条件beginset @sqlTmp = @fldName + ' From ' + @tblNameset @strTmp = @SqlSelect+' @Counts='+@SqlCounts+' FROM '+@tblNameset @strID = ' From ' + @tblNameendelsebeginset @sqlTmp = + @fldName + 'From ' + @tblName + ' where (1>0) ' + @strConditionset @strTmp = @SqlSelect+' @Counts='+@SqlCounts+' FROM '+@tblName + ' where (1>0) '
+ @strConditionset @strID = ' From ' + @tblName + ' where (1>0) ' + @strConditionend----取得查询结果总数量-----exec sp_executesql @strTmp,N'@Counts int out ',@Counts outdeclare @tmpCounts intif @Counts = 0set @tmpCounts = 1elseset @tmpCounts = @Counts--取得分页总数 set @pageCount=(@tmpCounts+@pageSize-1)/@pageSize/**当前页大于总页数 取最后一页**/if @page>@pageCountset @page=@pageCount--/*-----数据分页2分处理-------*/ declare @pageIndex int --总数/页大小 declare @lastcount int --总数%页大小set @pageIndex = @tmpCounts/@pageSizeset @lastcount = @tmpCounts%@pageSizeif @lastcount > 0set @pageIndex = @pageIndex + 1elseset @lastcount = @pagesize--//***显示分页 if @strCondition is null or @strCondition='' --没有设置显示条件 beginif @pageIndex<2 or @page<=@pageIndex / 2 + @pageIndex % 2 --前半部分数据处理 beginif @page=1set @strTmp=@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName+' order by '+ @fldSort +' '+ @strFSortTypeelsebeginif @Sort=1beginset @strTmp=@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName+' where '+@ID+' <(select min('+ @ID +') from ('+ @SqlSelect+' top ' + CAST(@pageSize*(@page-1) as Varchar(20)) +' '+ @ID +' from '+@tblName+' order by '+ @fldSort +' '+ @strFSortType+') AS TBMinID)'+' order by '+ @fldSort +' '+ @strFSortTypeendelsebeginset @strTmp=@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName+' where '+@ID+' >(select max('+ @ID +') from ('+ @SqlSelect+' top ' + CAST(@pageSize*(@page-1) as Varchar(20)) +' '+ @ID +' from '+@tblName+' order by '+ @fldSort +' '+ @strFSortType+') AS TBMinID)'+' order by '+ @fldSort +' '+ @strFSortTypeendendendelsebeginset @page = @pageIndex-@page+1 --后半部分数据处理 if @page <= 1 --最后一页数据显示 set @strTmp=@SqlSelect+' * from ('+@SqlSelect+' top ' + CAST(@lastcount as VARCHAR(4))+' '+ @fldName+' from '+@tblName+' order by '+ @fldSort +' '+ @strSortType+') AS TempTB'+' order by '
+ @fldSort +' '+ @strFSortTypeelseif @Sort=1beginset @strTmp=@SqlSelect+' * from ('+@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' ' + @fldName+' from '+@tblName+' where '+@ID+' >(select max('+ @ID +') from('+ @SqlSelect+' top ' + CAST(@pageSize*(@page-2)+@lastcount as Varchar(20)) +' '+ @ID +' from '+@tblName+' order by '+ @fldSort +' '+ @strSortType+') AS TBMaxID)'+' order by '+ @fldSort +' '+ @strSortType+') AS TempTB'+' order by '+ @fldSort +' '
+ @strFSortTypeendelsebeginset @strTmp=@SqlSelect+' * from ('+@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4)) +' '+ @fldName+' from '+@tblName+' where '+@ID+' <(select min('+ @ID +') from('+ @SqlSelect+' top ' + CAST(@pageSize*(@page-2)+@lastcount as Varchar(20)) +' '+ @ID +' from '+@tblName+' order by '+ @fldSort +' '+ @strSortType+') AS TBMaxID)'+' order by '+ @fldSort +' '+ @strSortType+') AS TempTB'+' order by '+ @fldSort +' '
+ @strFSortTypeendendendelse --有查询条件 beginif @pageIndex<2 or @page<=@pageIndex / 2 + @pageIndex % 2 --前半部分数据处理 beginif @page=1set @strTmp=@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName+' where 1=1 ' + @strCondition + ' order by '+ @fldSort +' '+ @strFSortTypeelse if(@Sort=1)beginset @strTmp=@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName+' where '+@ID+' <(select min('+ @ID +') from ('+ @SqlSelect+' top ' + CAST(@pageSize*(@page-1) as Varchar(20)) +' '+ @ID +' from '+@tblName+' where (1=1) ' + @strCondition +' order by '+ @fldSort +' '+ @strFSortType+') AS TBMinID)'+' '+ @strCondition +' order by '+ @fldSort +' '+ @strFSortTypeendelsebeginset @strTmp=@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' '+ @fldName+' from '+@tblName+' where '+@ID+' >(select max('+ @ID +') from ('+ @SqlSelect+' top ' + CAST(@pageSize*(@page-1) as Varchar(20)) +' '+ @ID +' from '+@tblName+' where (1=1) ' + @strCondition +' order by '+ @fldSort +' '+ @strFSortType+') AS TBMinID)'+' '+ @strCondition +' order by '+ @fldSort +' '+ @strFSortTypeendendelsebeginset @page = @pageIndex-@page+1 --后半部分数据处理 if @page <= 1 --最后一页数据显示 set @strTmp=@SqlSelect+' * from ('+@SqlSelect+' top ' + CAST(@lastcount as VARCHAR(4))+' '+ @fldName+' from '+@tblName+' where (1=1) '+ @strCondition +' order by '+ @fldSort +' '+ @strSortType+') AS TempTB'
+' order by '+ @fldSort +' '+ @strFSortTypeelse if(@Sort=1)set @strTmp=@SqlSelect+' * from ('+@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' ' + @fldName+' from '+@tblName+' where '+@ID+' >(select max('+ @ID +') from('+ @SqlSelect+' top '+ CAST(@pageSize*(@page-2) +@lastcount as Varchar(20)) +' '+ @ID +' from '+@tblName+' where (1=1) '+ @strCondition +' order by '+ @fldSort +' '+ @strSortType+') AS TBMaxID)'+' '+ @strCondition+' order by '+ @fldSort +' '+ @strSortType+') AS TempTB'+' order by '
+ @fldSort +' '+ @strFSortTypeelseset @strTmp=@SqlSelect+' * from ('+@SqlSelect+' top '+ CAST(@pageSize as VARCHAR(4))+' ' + @fldName+' from '+@tblName+' where '+@ID+' <(select min('+ @ID +') from('+ @SqlSelect+' top ' + CAST(@pageSize*(@page-2)+@lastcount as Varchar(20)) +' '+ @ID +' from '+@tblName+' where (1=1) '+ @strCondition +' order by '+ @fldSort +' '+ @strSortType+') AS TBMaxID)'+' '+ @strCondition+' order by '+ @fldSort +' '+ @strSortType+') AS TempTB'+' order by '
+ @fldSort +' '+ @strFSortTypeendend------返回查询结果-----exec sp_executesql @strTmpselect datediff(ms,@timediff,getdate()) as 耗时--print @strTmpSET NOCOUNT OFFGO
执行示例：
exec proc_paged_2part_selectMax 'tb_testTable',
'ID,userName,userPWD,userEmail',10,100000,'ID',0,null,'ID',0
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