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.
Tuning ‘log file sync’ Event
The log file sync wait occurs at the end of a transaction (COMMIT or End Of Job)and the database writer (DBWR) process must wait for the log file to synchronize with the database.
Troubleshooting wait event: ‘latch: row cache objects’
This latch comes into play when user processes are attempting to access or update the cached data dictionary values.
ORA-00600 [qkssao2s1] internal error issue
ORA-00600: internal error code, arguments: [ORA-00600: internal error code, arguments: [qkssao2s1], [], [], [], [], [], [], []
SQL hint mean force? More about parallel(二)(不并行的场景)
sql中如果使用了parallel hint 或是force parallel query 想并行查询的特性，如果那样做了就一定能保证 query optimizer选择并行的执行计划么？知道那样做实际上产生什么样的影响么？
More about ITL in oracle
ITL(Interested Transaction List ),The Oracle database engine locks the data modified by a transaction at the row level. To implement this feature every data block contains a list of all transactions that are modifying it. This list is commonly called interested transaction list (ITL).
Oracle GoldenGate Trail File
Trail files are generated by both the original extract and the Data Pump (extract) process. Trail files are read by the Data Pump (extract) and Replicat (replicat) processes
Script: Who’s using a database link?(找出谁在使用dblink)
Every once in awhile it is useful to find out which ses […]
Tuning PGA Memory
You can get the correct size of PGA using V$PGA_TARGET_ADVICE, dynamic performance view.
HAVING expression default Selectivity
In some cases the query optimizer might can not accurately estimate cardinality (e.g. group by having or like with bind variables cause etc..),therefore the Cardinality estimates are based on default seletivity of build-in oracle coredefault seletivity(5%).
oracle forall instructs must be followed by DML
Oracle BULK COLLECT and Oracle FORALL are the new featu […]
goldengate extract process abending caused by nologging DDL
I use goldengate(for oracle) to do a SCHEMA synchronize […]
