??xml version="1.0" encoding="utf-8" standalone="yes"?>女bbbbxxxx另类亚洲,亚洲成aⅴ人片久青草影院按摩,亚洲经典在线观看http://m.tkk7.com/anymobile/category/5740.htmlMake Anything Mobile!zh-cnSat, 01 Sep 2007 01:47:18 GMTSat, 01 Sep 2007 01:47:18 GMT60MySQL的limit参数http://m.tkk7.com/anymobile/articles/141857.htmlXu JianxiangXu JianxiangFri, 31 Aug 2007 18:14:00 GMThttp://m.tkk7.com/anymobile/articles/141857.htmlhttp://m.tkk7.com/anymobile/comments/141857.htmlhttp://m.tkk7.com/anymobile/articles/141857.html#Feedback0http://m.tkk7.com/anymobile/comments/commentRss/141857.htmlhttp://m.tkk7.com/anymobile/services/trackbacks/141857.html
limit参数在数据小时效率非帔RQ随着数据量的增大Q速度呈线性下降,q时候就可以昄出range的优势了?br />
比如有张表有35w条数据,不算大,一ơquery需要不的内存Q如果要分批/页查询的话Q如select * from car order by id limit offset, nums+offsetQ第一ơ查?0w条,则第二次只可以查?w条,W三?w条,……而且C后面数据q会出现重复现象?br />
select * from car order by id limit 0, 100000;
select * from car order by id limit 100001, 150000;
select * from car order by id limit 150001, 180000;
……

集合limit和range可以很好的解册个问题:

select * from car order by id asc limit 0, 100000;
# query {max id} from this list
……
select * from car order by id desc limit 0, 100000;
# query {min id} from this list
……
select * from car where id > {max id} and id < {min id} order by id;

d耗时20s左右Q?br />

Xu Jianxiang 2007-09-01 02:14 发表评论
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Oracle 数据库迁U?/title><link>http://m.tkk7.com/anymobile/articles/122357.html</link><dc:creator>Xu Jianxiang</dc:creator><author>Xu Jianxiang</author><pubDate>Wed, 06 Jun 2007 06:31:00 GMT</pubDate><guid>http://m.tkk7.com/anymobile/articles/122357.html</guid><wfw:comment>http://m.tkk7.com/anymobile/comments/122357.html</wfw:comment><comments>http://m.tkk7.com/anymobile/articles/122357.html#Feedback</comments><slash:comments>0</slash:comments><wfw:commentRss>http://m.tkk7.com/anymobile/comments/commentRss/122357.html</wfw:commentRss><trackback:ping>http://m.tkk7.com/anymobile/services/trackbacks/122357.html</trackback:ping><description><![CDATA[<p>1、执行exp命oQ导出dmp文g</p> <p>q移某些?br>exp <a href="mailto:username/password@db_name">username/password@db_name</a> tables=(table1,table2) file=filepath.dmp<br>q移某个用户下的数据?br>exp <a href="mailto:username/password@db_name">username/password@db_name</a> owner=(user1,user2) file=filepath.dmp<br>q移整个数据?br>exp username/password file=filepath.dmp full=y</p> <p>异常QORA-28009: connection to sys should be as sysdba or sysoper<br>Ҏ(gu)Q?br>exp userid='username/password as sysdba' owner=(user1,user2) file=filepath.dmp<br>=exp 'username/password as sysdba' owner=(user1,user2) file=filepath.dmp<br>或者输入exp后,在系l提C入用户名的时候,输入“username as sysdba”Q其它按提示输入?/p> <p>2、上传到数据库服务器</p> <p>3、新建数据库用户Qusername</p> <p>4、执行imp命oQ导入dmp文g</p> <p>exp <a href="mailto:username/password@db_name">username/password@db_name</a> fromuser=user touser=user1 file=filepath.dmp log=logfilepath<br>exp userid='username/password as sysdba' fromuser=user touser=user1 file=filepath.log</p> <p>?EXP和IMP的命令帮助:</p> <p> <table style="WIDTH: 650px; BORDER-COLLAPSE: collapse" cellSpacing=0 cellPadding=3 border=1> <tbody> <tr> <td style="BACKGROUND-COLOR: #e8e8e8">exp help=y</td> </tr> <tr> <td> <p>通过输入 EXP 命o和用户名/口oQ?zhn)可?br>在用?/ 口o之后的命?</p> <p>实例: EXP SCOTT/TIGER</p> <p>或者,(zhn)也可以通过输入跟有各种参数?EXP 命o来控?#8220;导出”<br>的运行方式。要指定参数Q?zhn)可以使用关键?</p> <p>格式: EXP KEYWORD=value ?KEYWORD=(value1,value2,...,valueN)<br>实例: EXP SCOTT/TIGER GRANTS=Y TABLES=(EMP,DEPT,MGR)<br>?TABLES=(T1: P1,T1: P2)Q如?T1 是分</p> <p>USERID 必须是命令行中的W一个参数?/p> <p>关键?nbsp; 说明Q默认)        关键?nbsp;     说明Q默认)<br>--------------------------------------------------------------------------<br>USERID   用户?口o            FULL         导出整个文g (N)<br>BUFFER   数据~冲区的大小          OWNER        所有者用户名列表<br>FILE     输出文g (EXPDAT.DMP)    TABLES       表名列表<br>COMPRESS 导入一个范?(Y)   RECORDLENGTH  IO 记录的长?br>GRANTS  导出权限 (Y)            INCTYPE      增量导出cd<br>INDEXES 导出索引 (Y)           RECORD       跟踪增量导出 (Y)<br>ROWS    导出数据?(Y)         PARFILE      参数文g?br>CONSTRAINTS 导出限制 (Y)    CONSISTENT   交叉表一致?br>LOG      屏幕输出的日志文?nbsp;   STATISTICS  分析对象 (ESTIMATE)<br>DIRECT   直接路径 (N)              TRIGGERS     导出触发?(Y)<br>FEEDBACK 昄?x ?(0) 的进?br>FILESIZE 各{储文件的最大尺?br>QUERY    选定导出表子集的子句</p> <p>下列关键字仅用于可传输的表空?br>TRANSPORT_TABLESPACE 导出可传输的表空间元数据 (N)<br>TABLESPACES 传输的表空间列?/p> </td> </tr> </tbody> </table> <br> <table style="WIDTH: 650px; BORDER-COLLAPSE: collapse" cellSpacing=0 cellPadding=3 border=1> <tbody> <tr> <td style="BACKGROUND-COLOR: #e8e8e8">imp help=y</td> </tr> <tr> <td> <p>可以通过输入 IMP 命o和?zhn)的用户?口o<br>跟有(zhn)的用户?/ 口o的命?</p> <p>实例: IMP SCOTT/TIGER</p> <p>或? 可以通过输入 IMP 命o和各U自变量来控?#8220;导入”<br>按照不同参数。要指定参数Q?zhn)可以使用关键?</p> <p>格式: IMP KEYWORD=value ?KEYWORD=(value1,value2,...,vlaueN)<br>实例: IMP SCOTT/TIGER IGNORE=Y TABLES=(EMP,DEPT) FULL=N<br>?TABLES=(T1: P1,T1: P2)Q如?T1 是分</p> <p>USERID 必须是命令行中的W一个参数?/p> <p>关键?nbsp; 说明Q默认)         关键?nbsp;     说明Q默认)<br>--------------------------------------------------------------------------<br>USERID  用户?口o            FULL         导入整个文g (N)<br>BUFFER  数据~冲区大?nbsp;         FROMUSER     所有h用户名列?br>FILE    输入文g (EXPDAT.DMP) TOUSER       用户名列?br>SHOW    只列出文件内?(N)  TABLES       表名列表<br>IGNORE  忽略创徏错误 (N)     RECORDLENGTH IO 记录的长?br>GRANTS  导入权限 (Y)            INCTYPE      增量导入cd<br>INDEXES 导入索引 (Y)           COMMIT       提交数组插入 (N)<br>ROWS    导入数据?(Y)         PARFILE      参数文g?br>LOG     屏幕输出的日志文?nbsp;  CONSTRAINTS  导入限制 (Y)<br>DESTROY 覆盖表空间数据文?(N)<br>INDEXFILE 表/索引信息写入指定的文?br>SKIP_UNUSABLE_INDEXES  跌不可用烦引的l护 (N)<br>ANALYZE  执行转储文g中的  ANALYZE 语句 (Y)<br>FEEDBACK 昄?x ?(0) 的进?br>TOID_NOVALIDATE  跌指定cd id 的校?br>FILESIZE 各{储文件的最大尺?br>RECALCULATE_STATISTICS 重新计算l计?(N)</p> <p>下列关键字仅用于可传输的表空?br>TRANSPORT_TABLESPACE 导入可传输的表空间元数据 (N)<br>TABLESPACES 要传输到数据库的表I间<br>DATAFILES 要传输到数据库的数据文?br>TTS_OWNERS 拥有可传输表I间集中数据的用?/p> </td> </tr> </tbody> </table> </p> <p> Q完Q?/p> <img src ="http://m.tkk7.com/anymobile/aggbug/122357.html" width = "1" height = "1" /><br><br><div align=right><a style="text-decoration:none;" href="http://m.tkk7.com/anymobile/" target="_blank">Xu Jianxiang</a> 2007-06-06 14:31 <a href="http://m.tkk7.com/anymobile/articles/122357.html#Feedback" target="_blank" style="text-decoration:none;">发表评论</a></div>]]></description></item><item><title>Win2k3下配|WinWebMailhttp://m.tkk7.com/anymobile/articles/115315.htmlXu JianxiangXu JianxiangFri, 04 May 2007 07:35:00 GMThttp://m.tkk7.com/anymobile/articles/115315.htmlhttp://m.tkk7.com/anymobile/comments/115315.htmlhttp://m.tkk7.com/anymobile/articles/115315.html#Feedback0http://m.tkk7.com/anymobile/comments/commentRss/115315.htmlhttp://m.tkk7.com/anymobile/services/trackbacks/115315.html操作pȝQWin 2003 Server SP2
杀毒YӞNorton 10.0企业?br>防火墙YӞBlackIce 3.6
软g版本QWinWebMail Server v3.7.3.1 标准?br>服务器:设有固定IPQ?21.*.*.*Q,托管在电(sh)信机?br>
操作步骤如下Q?br>1。域名(m****.comQ解析添加MX记录Qemail.m****.com
2。设|email.m****.com的A记录Q填入固定IPQ?21.*.*.*Q?br>3。服务器上安装WinWebMail Server?D:\WinWebMail
4。设|Mail Server的DNS为服务器|络q接中的DNSQ设|HELO为m****.comQ成功启动服?br>5。设|安装目录ؓUSER全权
6。在IIS中添加执行该目录的应用,q启IIS
7。在MS防火墙中开头HTTP/80QSMTP/25和POP/110端口的TCP

dMail Server的管理程序,发邮件到GMAIL账户QGMAIL很快可以收到邮g。-Q发送邮件OKQ?br>新徏一个̎户pirateQ在本机通过理E序可以收到。-Q接受内|邮件成功!
通过GMAILQ回邮gl[email=admin@m****.com]admin@m****.com[/email]无错误提C邮件返回,admind理E序也没收到q些邮g。-Q?font color=red>接受外网邮gp|Q?/strong>

同样在MS-DOSH口执行 telnet m****.com 25Q内|成功显C:
220 ESMTP on WinWebMail [3.7.3.1] ready. http://www.winwebmail.com
但是Q在外网执行同样的命令,却没有Q何回应!Q(问题应该出在这Q?/strong>

原来是BlackIce防火墙也需要开?5端口Q?br>Tools --> Advinced Firewall SettingsQAdd "SMTP"Q勾选All AddressQport?5QType选TCPQMode选AcceptQDuration Of Date选foreverQ点?#8220;Add”按钮Q设|完成!

telnet ip 25QpassQ可以接受外|的mail了!
 

参考文:

win2k3 下安?WinWebMail 3.7.3.1 ȝ大全
http://www.5dmail.net/bbs/thread-115284-1-1.html

WinWebMail常见问题解答
http://www.winwebmail.com/faq.html#2



Xu Jianxiang 2007-05-04 15:35 发表评论
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几个查数据库性能的SQL语句http://m.tkk7.com/anymobile/articles/35328.htmlXu JianxiangXu JianxiangTue, 14 Mar 2006 17:42:00 GMThttp://m.tkk7.com/anymobile/articles/35328.htmlhttp://m.tkk7.com/anymobile/comments/35328.htmlhttp://m.tkk7.com/anymobile/articles/35328.html#Feedback0http://m.tkk7.com/anymobile/comments/commentRss/35328.htmlhttp://m.tkk7.com/anymobile/services/trackbacks/35328.html

几个常用?/SPAN>SQL语句Q?BR>


1
?/SPAN>查低效率的语?SPAN lang=EN-US>

select executions , disk_reads, buffer_gets,round((buffer_gets-disk_reads)/buffer_gets,2) hit_radio,

round(disk_reads/executions,2) reads_per_run, sql_text

from v$sqlarea

where executions>1 --1表示执行ơ数过一?/SPAN>

and buffer_gets > 0

and (buffer_gets-disk_reads)/buffer_gets < 0.8 -- disk_reads是读盘的数?/SPAN>

order by 4 desc;

2、检查目前打开的游标情?/SPAN>

select sql_text,count(1) from v$open_cursor where user_name='X' group by sql_text order by count(1) desc;

3?/SPAN>查指定时间的语句情况

select * from v$sql s where first_load_time<'2006-03-01/00:00:00' order by s.EXECUTIONS desc;

-- 2?3?/SPAN>以后载入的语?/SPAN>

 

4?/SPAN>查执行时?st1:chsdate IsROCDate="False" IsLunarDate="False" Day="13" Month="2" Year="2006" w:st="on">2?SPAN lang=EN-US>13?/st1:chsdate>以后过30U的语句
select * from v$session_longops s where s.start_time>'28-feb-06' and s.LAST_UPDATE_TIME-s.START_TIME>30/1440/60 order by start_time;

 
备注Q?BR>v$open_cursor 已经打开的游标,Ҏ(gu)做的有数据库操作的程序可以通过查这个视图来认游标的用情?

v$session 当前q接到数据库服务器的用户名和q接?

v$sql 所有执行过的数据库语句

v$session_longops 执行旉较长的语?



Xu Jianxiang 2006-03-15 01:42 发表评论
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