oracle 12c new feature: moving online datafiles(在线移动数据文件)
在12c以前如果想移动表空间的数据文件首先要offline.再OS mv命令移动离线的数据文件到新路径，Recover datafile[ or tablespace or database] 再Online.从12c 开始可以移动Online 的数据文件了。
案例：latch: cache buffers chains event tuning
前两天对oracle数据库(single instance)进行了迁移升级从10.2.0.4 升到11.2.0.3，有一个项目迁完后第二天，cpu负载升到了130更高（16cpus）. 向用户询问后使用上没有改变，平时就几个人使用，而该用户活动会话就有100多个。最在等待CBC latch. 怀疑是执行计划发生了改变。
oracle 12c Database Architecture (CDB、PDB)
Database Architecture consists of
1) Container Database (CDB)
2) Pluggable Database (PDB)
Expdp Exclude schemas or tables while full=y(排除指定schema的全备份)
当做EXPDP 逻辑备份时常用到FULL=Y 的全库备份,但是有些schema不想每次都备份如一些自带的schemas(如APEX_030200),这时可以使用exclude很方便的排除…
About redo log wait events
log file sync wait 默认是发生在前台进程发进commits时比如用户commit,DDL,递归操作发生在dictionary table 上的DML,同时rollback 也会导致…
How to hanganalyze and systemstate dumps for Oracle database？
Oracle support request hang analysis and system state d […]
How to Encrypt Your Bash Shell Script on Linux Using SHC?(加密shell script)
当需要写shell连接数据库取一些数据或备份等操作时，shell中可能包含数据库的用户密码等敏感信息，被一些不怀好意的人发现是你的灾难，出于安全的考虑需要对shell明文加密，使用shc 就可以把原shell编译为可执行程序(二进制)，这样就无法再明文打开shell。
Manually create Oracle 11g physical standby DG ,Switchover, Convert to Logical standby(Scripts and Short Descriptions)
Manually create physical standby with rman;
Primary role and Primary standby role switchover;
Converting Physical Standby to Logical Standby ;
CTAS will loss default value define on columns
The CTAS operation although copies column constraints such as NULL, NOT NULL from the normal table to the partitioned table during the partitioned table creation, it does not copy DEFAULT VALUEs of the columns.
script:purge ADR file
[oracle@db231 ~]$ ./adr_purge
INFO: Purge started at Thu May 16 07:35:32 CST 2013
INFO: adrci purge started at Thu May 16 07:35:32 CST 2013
INFO: adrci purging diagnostic destination diag/tnslsnr/db231/listener
INFO: purging ALERT older than 90 days …
INFO: purging INCIDENT older than 30 days …
ORA-12034: materialized view log on xx.xx younger than last refresh when a mview fast refresh after Impdp
ORA-12012: error on auto execute of job 88
ORA-12034: materialized view log on “TOPBOX”.”TOPBOX_COURSESTUDY” younger than last refresh
ORA-06512: at “SYS.DBMS_SNAPSHOT”, line 2256
About ORACLE CPU, PSU, SPU Patch Nomenclature
It all started in January 2005 with Critical Patch Updates (CPU). Then Patch Set Updates (PSU) were added as cumulative patches that included priority fixes as well as security fixes.
linux发送手机短信 利用fesion robot
系统监控对于严重紧急的问题发短信通知，利用中国移动的飞信就可以做到免费给飞信好友发送sms短信,飞信机器人就是调用飞信的接口，可以命令行下调用。我们恰好可以利用这点。
Tuning “Read by other session wait” Event
This wait event occurs when we are trying to access a buffer in the buffer cache but we find that the buffer is currently being read from disk by another user so we need to wait for that to complete before we can access it.
