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如何在高并发分布式系统中生成全局唯一Id

 

又一个多月没冒泡了,其实最近学了些东西,但是没有安排时间整理成博文,后续再奉上。最近还写了一个发邮件的组件以及性能测试请看 《NET开发邮件发送功能的全面教程(含邮件组件源码)》 ,还弄了个MSSQL参数化语法生成器,会在9月整理出来,有兴趣的园友可以关注下我的博客。

 

分享原由,最近公司用到,并且在找最合适的方案,希望大家多参与讨论和提出新方案。我和我的小伙伴们也讨论了这个主题,我受益匪浅啊……

 

博文示例:

1.         GUID生成Int64值后是否还具有唯一性测试

2.         Random生成高唯一性随机码

 

今天分享的主题是:如何在高并发分布式系统中生成全局唯一Id

但这篇博文实际上是“半分享半讨论”的博文:

1)         半分享是我将说下我所了解到的关于今天主题所涉及的几种方案。

2)         半讨论是我希望大家对各个方案都说说自己的见解,更加希望大家能提出更好的方案。(我还另外提问在此:http://q.cnblogs.com/q/53552/上面已有几位园友回复(感谢dudu站长的参与),若你们有见解和新方案就在本博文留言吧,方便我整理更新到博文中,谢谢!)

 

我了解的方案如下……………………………………………………………………

1、  使用数据库自增Id

优势:编码简单,无需考虑记录唯一标识的问题。

缺陷:

1)         在大表做水平分表时,就不能使用自增Id,因为Insert的记录插入到哪个分表依分表规则判定决定,若是自增Id,各个分表中Id就会重复,在做查询、删除时就会有异常。

2)         在对表进行高并发单记录插入时需要加入事物机制,否则会出现Id重复的问题。

3)         在业务上操作父、子表(即关联表)插入时,需要在插入数据库之前获取max(id)用于标识父表和子表关系,若存在并发获取max(id)的情况,max(id)会同时被别的线程获取到。

4)         等等。

结论:适合小应用,无需分表,没有高并发性能要求。

2、  单独开一个数据库,获取全局唯一的自增序列号或各表的MaxId

1)         使用自增序列号表

专门一个数据库,生成序列号。开启事物,每次操作插入时,先将数据插入到序列表并返回自增序列号用于做为唯一Id进行业务数据插入。

注意:需要定期清理序列表的数据以保证获取序列号的效率;插入序列表记录时要开启事物。

使用此方案的问题是:每次的查询序列号是一个性能损耗;如果这个序列号列暴了,那就杯具了,你不知道哪个表使用了哪个序列,所以就必须换另一种唯一Id方式如GUID

2)         使用MaxId表存储各表的MaxId

专门一个数据库,记录各个表的MaxId值,建一个存储过程来取Id,逻辑大致为:开启事物,对于在表中不存在记录,直接返回一个默认值为1的键值,同时插入该条记录到table_key表中。而对于已存在的记录,key值直接在原来的key基础上加1更新到MaxId表中并返回key

使用此方案的问题是:每次的查询MaxId是一个性能损耗;不过不会像自增序列表那么容易列暴掉,因为是摆表进行划分的。

详细可参考:《使用MaxId表存储各表的MaxId值,以获取全局唯一Id

                   我截取此文中的sql语法如下:

第一步:创建表
create table table_key
(
       table_name   varchar(50) not null primary key,
       key_value    int         not null
)


第二步:创建存储过程来取自增ID
create procedure up_get_table_key
(
   @table_name     varchar(50),
   @key_value      int output
)
as
begin
     begin tran
         declare @key  int
         
         --initialize the key with 1
         set @key=1
         --whether the specified table is exist
         if not exists(select table_name from table_key where table_name=@table_name)
            begin
              insert into table_key values(@table_name,@key)        --default key vlaue:1
            end
         -- step increase
         else    
            begin
                select @key=key_value from table_key with (nolock) where table_name=@table_name
                set @key=@key+1
                --update the key value by table name
                update table_key set key_value=@key where table_name=@table_name
            end
        --set ouput value
    set @key_value=@key

    --commit tran
    commit tran
        if @@error>0
      rollback tran
end

感谢园友的好建议:

1.         @_)建议给table_key中为每个表初始化一条key1的记录,这样就不用每次if来判断了。

2.         @乐活的CodeMonkey)建议给存储过程中数据库事物隔离级别提高一下,因为出现在CS代码层上使用如下事物代码会导致并发重复问题.

TransactionOptions option = new TransactionOptions();
option.IsolationLevel = IsolationLevel.ReadUncommitted;
option.Timeout = new TimeSpan(0, 10, 0);
 
using (TransactionScope transaction = new TransactionScope(TransactionScopeOption.RequiresNew, option))
{
        //调用存储过程
}

在咨询过DBA后,这个存储过程提高数据库隔离级别会加大数据库访问压力,导致响应超时问题。所以这个建议我们只能在代码编写宣导上做

3.         @土豆烤肉)存储过程中不使用事物,一旦使用到事物性能就急剧下滑。直接使用UPDATE获取到的更新锁,即SQL SERVER会保证UPDATE的顺序执行。(已在用户过千万的并发系统中使用)

create procedure [dbo].[up_get_table_key]
(
   @table_name     varchar(50),
   @key_value      int output
)
as
begin

	SET NOCOUNT ON;
	DECLARE @maxId INT
	UPDATE table_key
	SET @maxId = key_value,key_value = key_value + 1 
	WHERE table_name=@table_name
	SELECT @maxId

end

结论:适用中型应用,此方案解决了分表,关联表插入记录的问题。但是无法满足高并发性能要求。同时也存在单点问题,如果这个数据库cash掉的话……

我们目前正头痛这个问题,因为我们的高并发常常出现数据库访问超时,瓶颈就在这个MaxId表。我们也有考虑使用分布式缓存(egmemcached)缓存第一次访问MaxId表数据,以提高再次访问速度,并定时用缓存数据更新一次MaxId表,但我们担心的问题是:

a)         倘若缓存失效或暴掉了,那缓存的MaxId没有更新到数据库导致数据丢失,必须停掉站点来执行Select max(id)各个表来同步MaxId表。

b)         分布式缓存不是一保存下去,其他服务器上就立马可以获取到的,即数据存在不确定性。(其实也是缓存的一个误用,缓存应该用来存的是频繁访问并且很少改动的内容)

         改进方案:

整体思想:建立两台以上的数据库ID生成服务器,每个服务器都有一张记录各表当前IDMaxId表,但是MaxId表中Id的增长步长是服务器的数量,起始值依次错开,这样相当于把ID的生成散列到每个服务器节点上。例如:如果我们设置两台数据库ID生成服务器,那么就让一台的MaxId表的Id起始值为1(或当前最大Id+1),每次增长步长为2,另一台的MaxId表的ID起始值为2(或当前最大Id+2),每次步长也为2。这样就将产生ID的压力均匀分散到两台服务器上,同时配合应用程序控制,当一个服务器失效后,系统能自动切换到另一个服务器上获取ID,从而解决的单点问题保证了系统的容错。(Flickr思想)

但是要注意:1、多服务器就必须面临负载均衡的问题;2、倘若添加新节点,需要对原有数据重新根据步长计算迁移数据。

结论:适合大型应用,生成Id较短,友好性比较好。(强烈推荐)

3、  Sequence特性

这个特性在SQL Server 2012Oracle中可用。这个特性是数据库级别的,允许在多个表之间共享序列号。它可以解决分表在同一个数据库的情况,但倘若分表放在不同数据库,那将共享不到此序列号。(egSequence使用场景:你需要在多个表之间公用一个流水号。以往的做法是额外建立一个表,然后存储流水号)

相关Sequence特性资料:

SQL Server2012中的SequenceNumber尝试

SQL Server 2012 开发新功能——序列对象(Sequence

identitysequence的区别

Difference between Identity and Sequence in SQL Server 2012

结论:适用中型应用,此方案不能完全解决分表问题,而且无法满足高并发性能要求。同时也存在单点问题,如果这个数据库cash掉的话……

4、  通过数据库集群编号+集群内的自增类型两个字段共同组成唯一主键

优点:实现简单,维护也比较简单。

缺点:关联表操作相对比较复杂,需要两个字段。并且业务逻辑必须是一开始就设计为处理复合主键的逻辑,倘若是到了后期,由单主键转为复合主键那改动成本就太大了。

结论:适合大型应用,但需要业务逻辑配合处理复合主键。

5、  通过设置每个集群中自增 ID 起始点(auto_increment_offset),将各个集群的ID进行绝对的分段来实现全局唯一。当遇到某个集群数据增长过快后,通过命令调整下一个 ID 起始位置跳过可能存在的冲突。

优点:实现简单,且比较容易根据 ID 大小直接判断出数据处在哪个集群,对应用透明。缺点:维护相对较复杂,需要高度关注各个集群 ID 增长状况。

结论:适合大型应用,但需要高度关注各个集群 ID 增长状况。

6、  GUIDGlobally Unique Identifier全局唯一标识符

GUID通常表示成3216进制数字(09AF)组成的字符串,如:{21EC2020-3AEA-1069-A2DD-08002B30309D},它实质上是一个128位长的二进制整数。

GUID制定的算法中使用到用户的网卡MAC地址,以保证在计算机集群中生成唯一GUID;在相同计算机上随机生成两个相同GUID的可能性是非常小的,但并不为0。所以,用于生成GUID的算法通常都加入了非随机的参数(如时间),以保证这种重复的情况不会发生。

优点:GUID是最简单的方案,跨平台,跨语言,跨业务逻辑,全局唯一的Id,数据间同步、迁移都能简单实现。

缺点:

1)         存储占了32位,且无可读性,返回GUID给客户显得很不专业;

2)         占用了珍贵的聚集索引,一般我们不会根据GUID去查单据,并且插入时因为GUID是无需的,在聚集索引的排序规则下可能移动大量的记录。

有两位园友主推GUID,无须顺序GUID方案原因如下:

@徐少侠           GUID无序在并发下效率高,并且一个数据页内添加新行,是在B树内增加,本质没有什么数据被移动,唯一可能的,是页填充因子满了,需要拆页。而GUID方案导致的拆页比顺序ID要低太多了(数据库不是很懂,暂时无法断定,大家自己认识)

@无色                我们要明白id是什么,是身份标识,标识身份是id最大的业务逻辑,不要引入什么时间,什么用户业务逻辑,那是另外一个字段干的事,使用base64(guid,uuid),是通盘考虑,完全可以更好的兼容nosql,key-value存储。

(推荐),但是倘若你系统一开始没有规划一个业务Id,那么将导致大量的改动,所以这个方案的最佳状态是一开始就设计业务Id,当然业务Id的唯一性也是我们要考虑的。

结论:适合大型应用;生成的Id不够友好;占据了32位;索引效率较低。

改进:

1)         @dudu提点)在SQL Server 2005中新增了NEWSEQUENTIALID函数。

详细请看:《理解newid()newsequentialid()

在指定计算机上创建大于先前通过该函数生成的任何 GUID GUID newsequentialid 产生的新的值是有规律的,则索引B+树的变化是有规律的,就不会导致索引列插入时移动大量记录的问题。

但一旦服务器重新启动,其再次生成的GUID可能反而变小(但仍然保持唯一)。这在很大程度上提高了索引的性能,但并不能保证所生成的GUID一直增大。SQL的这个函数产生的GUID很简单就可以预测,因此不适合用于安全目的。

a)         只能做为数据库列的DEFAULT VALUE,不能执行类似SELECT NEWSEQUENTIALID()的语句.

b)         如何获得生成的GUID.

如果生成的GUID所在字段做为外键要被其他表使用,我们就需要得到这个生成的值。通常,PK是一个IDENTITY字段,我们可以在INSERT之后执行 SELECT SCOPE_IDENTITY()<计业务font-而>只能做为数据库列的GUID.

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SQL产生的新的值-color:关联pannt-familyy: 宋返回amily: 宋GUIDGUIDId

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<-family: ffano-asc因此我专门写的a并发测试程序="feme-射给出测试结果截图及a码简单说明SELECT NEWSEQUENTIALIne-height: normal; text-indent: 0pt;" align="justify">Id"Tn;"a/span>Id"Tpan般程序上鬡缚安排错误处理机制-US比如异常eme-行pan>重插brei>SELECT NEWSEQUENTIALIne-height: normal; text-indent: 0pt;" align="justify">SQLpan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-f mso-fignze: 10.yellow;amily: 宋体; mso-fareast-theme-fan>

pan fignze: 10.yellow;aan style="line-height: normal;" lang="EN-US">SQLpan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-f mso-fignze: 10.yellow;amily: 宋体; mso-fareast-theme-fan>yle纯>字="span>pan fignze: 10.yellow;aan style="line-height: normal;" lang="EN-US">ne-height: normaaut1family: calibri;">NEWSEQe="font-family: calibri;">SQLne-height: normaaut1fapt;" align="justify">pan style=mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-faro>的语句NEWSEQfignze: 10.yellow;>pan s-farn stuagecaen-usnor-latin; mson stuagecazh-can>ne-height: normaaut1fapt;" align="justify">pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-a-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-f mso-an>NEWSEQfignze: 10.yellow;>pan s-farn stuagecaen-usnor-latin; mson stuagecazh-can>因简单和业务应用>GUID的语句.

<>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fan>码规则span>SELECT NEWSEQUENTIALIne-height: normal; text-indent: 0pt;" align="justify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme合an>

<>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fily: 宋体;合an>

>
Id<展yle庯次具;业务: 宋自己"码规则等等="
SELECT NEWSEQUENTIALIne-height: normal; text-indent: 0pt;" align="justify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fily: 宋体;span><-family: calibri; 缺陷cla根据具;"码规则实现而a同;还宋考虑倘若主键n业务上允许改变>Id"Tpla带来外键同步"麻烦SELECT NEWSEQUENTIALIs"font--height: normal; text-indent: 0pt;" align="justify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fily: 宋体;span> >SQLGUID的语句.

+3alibri; mspmilyi-theme-font="color: #000000;"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-familyareast-font-family: 宋体;span>位>务器"码align="justify"><>pan ="fcerun0.yesan>

<>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontsp这样就完全单机完rd-bword-全局/span"码="span>---span><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fan>共span>20le="font-familystyle=">

SELECT NEWSEQUENTIALIs42"line-height: normal;" lang="EN-US">NEWSEQUENTIALID

>码>少pan定的顺序>是有规律的fy: inter-ideograph; line-height:>
<-family: ffano-ascyleword-高/span>SELECT NEWSEQUENTIALID42"line-height: normal;" lang="EN-US">的语句.

+3alibri; mspmilyi-theme-font="color: #000000;"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme合位>务器"码align="justify"><>pan ="fcerun0.yesan>

据库和缓存="span>---span><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font共span>20le="font-familystyle=">

SELECT NEWSEQUENTIALIs42"line-height: normal;" lang="EN-US">Nspan><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

<>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font、序列表、ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-couSequencele="font-familystyle=">

SELECT NEWSEQUENTIALIs42"line-height: normal;" lang="EN-US">Nspan>

>SELECT NEWSEQUENTIALIs42"line-height: normal;" lang="EN-US">Nspan>SELECT NEWSEQUENTIALIs21.2"line-height: normal;" lang="EN-US">NEWSEQUENTIALIDSQLpan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-f mso-fignze: 10.yellow;amily: 宋体; mso-fareast-theme-fan>
<-family: calibri backgrnord- calibriffffansi->

SELECT NEWSEQUENTIALIne-height: normal; text-indent: 0pt;" align="justify">&-family: calibri; 2; msole="font-familystyle="hormal;" lang="EN-N mso-le="font-family: calibri;">SELECT NEWSEQUENTIALIne-height: normal; text-indent: 0pt;" align="justify">&-family: calibri; 2; msole="font-familystyle="hormal;" lang="EN-N mso-le="font-backgrnordy: 4bacc6; family: calibri;">SELECT NEWSEQUENTIALIne-height: normal; text-indent: 0pt;" align="justify">

pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

>SELECT NEWSEQUENTIALIne-height: normal; text-indent: 0pt;" align="justify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fily: 宋体;span><-family: calibri; 测试环境/span>SELECT NEWSEQUENTIALIne-height: normal; text-indent: 0pt;" align="justify"><>pan nEQUroof0.yesan normal; text-ispan>/spanpan>/106337/201308/16080801-db45c9adad8744288978a44f04b4d5de.jpgstyle="line-heightsimgpan>/spanpan>/106337/201308/16080802-a0e5e5f2abf449cd91c6560e6e8188e8.jpgstalt-h lip_image002lewidth="622leor: #0="381"nbamite="0" />"/a.66gd;" alormal;" lang="EN-N mso-le="font-family: calibri;">SELECT NEWSEQUENTIALIne-height: normal; text-indent: 0pt;" align="justify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fily: 宋体;span><-family: calibri; 主要测试思路span>

SELECT NEWSEQUENTIALID"mso-be-height: normal;" lang="EN-US">的语句.

<>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fily: 宋体;span><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font后再转为ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-couInt64argin-left: 3.6><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme合位值="f䔾入集合ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-couAargin-left: 3.6><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font、ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-couBargin-left: 3.6><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font、-hellia-ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-couN66gd;" align="justify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fily: 宋体;合an>

>SELECT NEWSEQUENTIALID"mso-be-height: normal;" lang="EN-US">的语句.

<>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fily: 宋体;合an>

>ont再 styleak: normal; marmsargin: 0cm 0cm 0pt 38.45pt; text-justify: inter-ideograph; line-height: normal; text-indent: 24.45pt; mso-char-indent-couDicbsp;aryalign="justify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font字典高效查ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-coukeyalign="justify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme合中word-b多pa集合全部加到ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-couDicbsp;aryalign="justify"ustify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>

>
ont左右-US所以每次并发"word-b/span值总>控制e此范围内"Tn测试达到最有效话
SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">N librstops: 244pan>onpan><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fily: 宋体;span>
<-family: calibri; 主要a码span>

<4<-loolba : truei <= Environmsty.ProcessorCnorm -1s i++) { Th: dPool.QueueUserWorkItem( (.5pt) =>- { US"><long>-mtempUS"> =l.5pt as US"><long>-- for (al; j =l1s j <l.5ptLengtUS"j++) { byte[] buffer =lGuid.NewGuid().ToByteArray()- tempUS">.Add(BitConver;" .ToInt64(buffer, 0))- } ba ri" .S>[i])- }s orermal;" lang="EN-N mso-le="font-family: calibri;">SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">N librstops: 244pan>onpan>

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">N/pan><>pan nEQUroof0.yesan normal; text-ispan>/spanpan>/106337/201308/16080802-006355ae6f674d1ca59046fd3982e8bd.jpgstyle="line-heightsimgpan>/spanpan>/106337/201308/16080802-b7d385423a064ea093ab946c2a211a0d.jpgstalt-h lip_image004lewidth="588leor: #0="35"nbamite="0" />"/a.66gd;" alormal;" lang="EN-N mso-le="font-family: calibri;">SELECT NEWSEQUENTIALIne-height: normal; text-indent: 0pt;" align="justify">SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>/spanpan>/106337/201308/16080803-62f60136ed0b4b8abc553ce5faee65df.pngstyle="line-heightsimgpan>/spanpan>/106337/201308/16080803-df53e12f2ceb40a0b1c04db43270fe="Mpngstalt-himagelewidth="514leor: #0="195"nbamite="0" />"/a.66ormal;" lang="EN-N mso-le="font-family: calibri;">SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>/spanpan>/106337/201308/16080803-c7df5f0ba75148a389b2c89b0d16b78f.pngstyle="line-heightsimgpan>/spanpan>/106337/201308/16080804-94893f591c044072af5db2ed27e5f498Mpngstalt-himagelewidth="516leor: #0="219"nbamite="0" />"/a.66ormal;" lang="EN-N mso-le="font-family: calibri;">SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SQLs/spanu/an>@Jn>SQL

fy: inter-ideograph; line-height: normal; text-indent: 24.45pt; mso-char-indent-cou(66gd;" align="jus="line->

fEN-US">SQL

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font桶数量span>

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

>ont倘若每縪桶brei会-均等bre="f则每縪桶break: normal; marmsargin: 0cm 0cm 0pt 38.45pt; text-justify: inter-ideograph; line-height: normal; text-indent: 24.45pt; mso-char-indent-cou style="font-familymsargin: 0cm 0cm 0p="color: #000000;"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>&-family: calibri; (2 ^ 128) / (2 ^ 64) = 2 ^ 64 =l18446744073709551616n>

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan><-family: calibri; 也就䘯说="f其实重复brei会-有bre="f只-概率的嚄SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan>="fle="font-familymsargin: 0cm 0cm 0p="color: #000000;"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

>
ont发"wo重复brei率是span>

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font&asyma-ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-cou 1 - ((1 - 1 / t-familymsargin: 0cm 0cm 0p="color: #000000;"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan>="ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-cou2 ^ 64)) ^ (2 ^ 32)) <l1 - 1 + 1 / (2 ^ 32) =l1 / (2 ^ 32) t-familymsargin: 0cm 0cm 0p="color: #000000;"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font&asyma-ak: normal; mar

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font<>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SQL

SQLSQL

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>SELECT NEWSEQUENTIALID"mso-be-height: normal;" lang="EN-US">的语句.

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<>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font做为ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-couRandomle="font-familyi-theme-font="color: #000000;"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font参数-U即ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-couRandomle="font-familymsargin: 0cm 0cm 0p="color: #000000;"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

SELECT NEWSEQUENTIALID"mso-be-height: normal;" lang="EN-US">的语句.

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>ont参数-U存在重复SELECT NEWSEQUENTIALID"mso-be-height: normal;" lang="EN-US">的语句.

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>ormstyleak: normal; marmsargin: 0cm 0cm 0pt 38.45pt; text-justify: inter-ideograph; line-height: normal; text-indent: 24.45pt; mso-char-indent-couunchecked((al;)Dateheig.Now.Ticksak: normal; marg><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font做为ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-couRandomle="font-familyustify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

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ont参数-U存在重复SELECT NEWSEQUENTIALID"mso-be-height: normal;" lang="EN-US">的语句.

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>ormstyleak: normal; marmsargin: 0cm 0cm 0pt 38.45pt; text-justify: inter-ideograph; line-height: normal; text-indent: 24.45pt; mso-char-indent-couGuid.NewGuid().GetHashCode(ak: normal; marg><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font做为ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-courandomle="font-familyustify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

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ont参数-Ui试不存在重复(或存在>SELECT NEWSEQUENTIALID"mso-be-height: normal;" lang="EN-US">的语句.

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>ormstyleak: normal; marmsargin: 0cm 0cm 0pt 38.45pt; text-justify: inter-ideograph; line-height: normal; text-indent: 24.45pt; mso-char-indent-couRNGCryptoServiceProvangralign="justify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font做为ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-courandomle="font-familyustify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

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ont参数-Ui试不存在重复(或存在>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan><-family: calibri; 即span>

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">&-family: calibri; = n noSystem.Security.Crypto"EN-Uy.RNGCryptoServiceProvangr()-ak: normal; mar"line-heormal;" lang="EN-N mso-le="font-family: calibri;">SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan>&-family: calibri; i试结果span>

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>< mso-no-proof0.yesan normal; text-ispan>/spanpan>/106337/201308/16080804-248877da032045a38e1e192eb4256057.jpgstyle="line-heightsimgpan>/spanpan>/106337/201308/16080804-c3130297cc3a4adbbb3cae404182ca60.jpgstalt-hclip_image007lewidth="618leor: #0="385"nbamite="0" />"/a.66p clas ormal;" lang="EN-N mso-le="font-family: calibri;">SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SQL

SQLSQL

eormal;" lang="EN-N mso-le="font-family: calibri;">SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>&-family: calibri; 2; msole

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>&-family: calibri; pan些精彩评

<="an>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>&-family: calibri; pan、ak: normal; mar"line-heormal;" lang="EN-N mso-le="font-family: calibri;">SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

<>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontSELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

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ont<>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontb系统>拼ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-coubytele="font-familyustify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

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ont<果数据库很少="fp搞这么aak: normal; marmsargin: 0cm 0cm 0pt 38.45pt; text-justify: inter-ideograph; line-height: normal; text-indent: 24.45pt; mso-char-indent-coubytele="font-familyustify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

>ont能-高>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

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ont<果数据库很大="fp搞这么aak: normal; marmsargin: 0cm 0cm 0pt 38.45pt; text-justify: inter-ideograph; line-height: normal; text-indent: 24.45pt; mso-char-indent-coubytele="font-familyustify"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

>ont不兼容索引不兼容缓存-U不是害自已吗-U/span>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

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ont<果数据库要求伸缩><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

>ont-US需要不断改程序-U不是自找苦吗-U/span>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

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ont<果数据库要求移植><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-fontan>

>ont-U移植起来不如重新设计="f这-pa是很多公司不断加班b原因-U/span>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>&-family: calibri; 2; msole

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan>&-family: calibri; pa依赖于数据存储系统>分层设计思想b精e="f实现战略>SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>&-family: calibri; 2; msole

SELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan>&rm不要迷信数据库<>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan>-U不要style自增ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-couidle="font-familyi-theme-font="color: #000000;"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan>-U不要style存储过程-U不要style内部函数-U不要style非标准ak: normal; maramily: 宋体; mso-fareast-theme- normal; text-indent: 24.45pt; mso-char-indent-cousqlle="font-familyi-theme-font="color: #000000;"><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan>-U存储系统只做存储系统b事<当出现系统><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan>-U实现/span><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-theme-font改造-U/span><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan>-U-U实现/span><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan>缓存/span><>pan style="lindi-fo="line-height: normal; mso-ascii-font-family: calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: mino mso-fareainor-latin: minost-font-family: 宋体; mso-fareast-themespan>&rmSELECT NEWSEQUENTIALIne-height:: normal;" lang="EN-US">Nspan>&-family: calibri; 2; msole

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mal/div>mamama ldiv lang = "postDesc">posted on 2013-08-16 08:15

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