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In a distributed database environment, using database link is a good choice, but sometimes It's tough for us to manage and maintain it. for example, if we change the password of source db name, we need to change it in target db source as well. Before Oracle version 11g, we must delete the link then create a new link to do so, but from Oracle 11.2 on, we can directly alter the database link to change the password. like that:alter database link dblinknameconnect to testidentified by newpsw;And if

I taught two days Oracle database OCP training courses last weekend with good performance my students told me that. The Oracle database training is a practical course for learner to do a lot of scenerios and understand the theory of Oracle database, so do not make your goal with obtaining the OCP certificate only. It's very important for you to get not only experience on how to manage and maintain Oracle database, but also learn Oracle from Oracle, because Oracle database has huge places for you

Last year I did a migration for three nodes' RAC DB from old machine into new machine.The whole replacement is wonderful with no risk and providing 7/24 HA, but I encountered a little problem about Web dbconsole that I couldn't reconfigure dbconsole successfully.[@more@]Some errors from emagent.trc as below:2011-02-06 10:03:07 Thread-4135253696 ERROR util.files: ERROR: nmeufis_new: failed in lfiopn on file: /local/bin/oracle/product/10.2.0/db_1/rac1_PRD11/sysman/emd/agntstmp.txt. error = 2 (No s

The TAF service name can not be registered into CRS,please see the below info:[oracle@racdb1 ~]$ crs_register ora.RACDB.racdb_taf.RACDB2.srvSyntax error in /oracle/crs_1/crs/public/ora.RACDB.racdb_taf.RACDB2.srv.cap, line number 1: "CRS-0210: Could not find resource 'ora.RACDB.racdb_taf.RACDB2.srv'."(File: caa_profile.cpp, line: 155[oracle@racdb1 ~]$ cd /oracle/crs_1/crs/public/ora.RACDB.racdb_taf.RACDB-bash: cd: /oracle/crs_1/crs/public/ora.RACDB.racdb_taf.RACDB: No such file or direc

Some days before, I helped my clients replace nodes in RAC DB. The replacement procedure was finished successfully, but I met a failure during the web dbcontrol reconfiguration.The following is the main output info, you could see that the process was terminated because the port 3938 is already used.[@more@]Some days before, I helped my clients replace nodes in RAC DB. The replacement procedure was finished successfully, but I met a failure during the web dbcontrol reconfiguration.The following i

In the past couple of months, I taught two serials of Oracle 10g OCP courses for WDP students in CNTIMES. A period of OCP course is 10 days and I took 20 days giving training during two periods. The happy thing is that the performance of my training is very good and my students have all made great improvement in Oracle Database. Here,I'd like to introduce a great chance for you to learn Oracle database and get certificate with easy and low-cost access.It's Oracle WDP which allows education insti

Here, I would like to keep a note for the installation of Oracle RAC DB.Last month, I failed in the installation for two times. First of all, I got an error about virtual network due to the wrong configuration of Network on VIP address.I can ping the VIPs before installation,this is totally uncorrect configuration. After disable the specified network card it worked fine.The second failure is about private network.The first node rebooted unfortunately when I run the script(root.sh) on the second

Today when I installed a new Oracle RAC DB, an error occured which is about "The specified nodes are not clusterable".The cluster nodes are in a domain network, and the public/private/virtual name are all with the domain name.Before I run the SHELL script .runInstaller.sh, I only run the security authentication commands to identify these issues:ssh node1.domain.com datessh node2.domain.com datessh node1-priv.domain.com datessh node2-priv.domain.com dateBut I didn't run the command like

My last blog article was posted one year ago here,it's coincidence that I logged in my blog today.It is a whole year which flied quickly,here I have to say really SORRY to the visitors who came to my blog with hope and left with nothing new.In the past one year,I spent more time enjoying my life with my family,reserching some new technologies on oracle.Some got,some lost......Tomorrow is nice and I'm ready to go,here I made a promise that I'd like to bring lots of new and valueable articles on d

I'v been back from USA for more than a week so far and everything is on the right track,like time difference,food,culture and environment etc.This trip is really impressive and absolutely unforgettable,and I'll keep it in mind as a great fortune forever.The American life is amazing at some points.For example,most of them own a big big house,whereas we just own a small small apartment;basically they drive a SUV car but a few of us drive a uncomfortable car;it is leisure time for them to work beca

Due to work and study,sorry for updating my web blog so late!In these several months there were great changes about me.First,I quited my job from Aspire for the consideration of working career.Second,I realized the importantance of English and made great progress on it.Third,It's my honor of being a member of a great foreign company which is expanding my career greatly.Finally,After succeeding in applying for passport and US visa,I'm about to go abord,because I'm going to the US for training nex

1、put the following file(login.sql) into $ORACLE_HOME；2、set environment virable：SQLPATH=$ORACLE_HOME3、the content of file(login.sql) as follows：define _editor=viset serveroutput on size 1000000set trimspool onset long 5000set linesize 100set pagesize 9999column plan_plus_exp format a80column global_name new_value gnameset termout offdefine gname=idlecolumn global_name new_value gnameselect lower(user) || '@' || substr( global_name, 1,decode( dot, 0, length(global_name), dot-1) ) global_nam

RAC：Oracle rac enables multiple independent servers that are linked by an interconnect to share access to database,providing ha,scalability,and redundancy during failure.RAC provide the benefit of the system failure,such as node failures and instance crashes;DG：dg ensures ha,data protection,and disaster recovery for enterprise data,it provide the benefit of the site failure.Flashback Database ：it provide fast recovery from logical data corruption and user errors.RMAN ：it is an utility that s

RPO(Recovery Point Objective) is focus on the loss of data;RTO(Recovery Time Objective) is focus on the loss of service.Some solutions for disaster recovery：1.Disk array copy technology(EMC SRDF,IBM PPRC,HP BusinessCopy,HDS TrueCopy);2.Storage volume copy technology(Veritas VVR);3.Datatabase copy technology(DSG RealSync,Quest SharePlex);4.Application copy technology.You should pay attention to three key considerations:TCO(Total Cost of the Ownership)ROI(Return On Investment)BCM(Business Continu

IBM最近提出了一个smarter planet的plan，旨在着手改善世界，使得人类赖以生存的星球更加智能。试想一下，如果我们能够通过改善电网就能节约50％左右的电能，如果我们能够改善交通就能节省途中时间、减少事故等，如果我们能够提升食品质量就能挽救无辜的生命等等。这不是如果，目前人类已经在打造这些如果成为fact。事实上，现在我们可以借助科技的力量来change这个星球。随着IT技术的发展，我们可以利用新的技术和新的理念来智能化这个世界上的任何事和物，使得它们变得更好，更有效，更加服务于我们这个星球。目前，该smarter planet还没

最近较闲，着手准备一些技能培训，其中涉及到SQL Tuning，如下是我总结出的10条SQL语句优化精髓：1、使用绑定变量；2、产生的redo和undo量越少越好；3、避免排序操作；4、避免复杂嵌套的语句；5、使用索引并正确利用上索引；6、控制好事务的粒度；7、走最优的执行计划；8、编写最佳的等价语句；9、可不可以使用上物化视图特性和分区特性；10、正确处理锁等待事件；这里每一条都可展开一个topic来讲解。先分享给大家，有时间再一一详细的阐述！[@more@]

要离开工作快4年的卓望(www.aspire-tech.com)了，要离开这座熟悉的深港基地大楼了。很感谢aspire让我成长，很感谢aspire的人和事。。。。。。欢迎大家推荐数据库的相关职位哈，最好base在深圳。thanks.[@more@]

HP Oracle Database Machine Hardware(all hardware components in one standard (42U) rack)8–HP Proliant DL360 G5 database servers, with• 2 quad-core Intel Xeon Processor E5430 (2.66GHz)• 32GB memory• 1–HP InfiniBand Dual Port HCA• 4–146GB SAS 10K hard disk drives4–24-port InfiniBand switches14–HP Exadata Storage Server Hardware—each is an HP ProLiant DL180 G5, with• 2 quad-core Intel Xeon Processor E5430 (2.66GHz)• 8GB memory• 1–HP InfiniBand Dual Po

在RAC的Oracle Net配置中有三种模式，这里记录一下：1、Connect-time Failover方式；只有一个service，会尝试第一个node，然后尝试另外的node可以failover，不过balance需手工当一个node发生故障时，该node上的事务丢失，会话丢失，自动重连。如下的例子：imall =(DESCRIPTION=(ADDRESS_LIST=(LOAD_BALANCE=OFF)(FAILOVER=ON)(ADDRESS=(PROTOCOL=TCP)(HOST=imall1)(PORT=1521))(ADDRESS=(PROTOCOL=TCP)(HOST=imall2)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=imall)))2、Load Balancing方式；[@more@]只有一个service，Oracle Net会尝试其

虽说10月底了，深圳的气候仍然像夏天一样炎热，只不过现在下班后那天是黑朦朦的。最近一直都很忙，应该说这大半年一直都很忙，忙中有乐忙中偷闲。首先祝贺自己通过了Oracle的OCM大师级别认证，让自己能更加深入学习和传播Oracle数据库。给二家软件公司培训Oracle的一系列课程也耗去了我的许多空闲时间，不过总体感觉下来效果还不错的，接下来还会有一个系列的培训课程应该是比较轻松的了。给一家医院做数据库的故障恢复就像是医生给病人看病一样，有时隔行还真的隔着大山。替一个老板负责他公司的系统优化工作耗去了我多个晚上的休息时间，