Compilation of oracle objects are pretty easy where there is no activity on the database. If the objects are heavily accessed and the compilation takes place then you should be prepared for the worst case scenarios.Depending on the object dependency and access rates, sometimes downtime is required. Offline the system and compile the objects and… Continue reading ORA-4068 Errors for Valid Objects
If there is a corruption on one of the datafiles on a dataguard you can restore the corruption using another dataguard. I will explain how to do the restore operation in rman using oracle 11.2. ON THE WORKING DATAGUARD Backup the datafile as image copy. RMAN> BACKUP AS COPY DATAFILE 178 FORMAT “+data/test2/datafile/test_datafile178”; Uncatalog the… Continue reading Restore Corrupt Datafile using Another Standby
Active Dataguard enables a dataguard to be open as read only and log apply at the same time. This way you can have near real time ( depending on the gap with your primary) read only copy of your primary system which has the all functionality of a normal dataguard. One of the cool features… Continue reading Active Dataguard in Action for Block Corruptions
Kernel upgrade can be applied node by node on exadata so there will be no service interruption. Kernel upgrades are required when you need new functionality or when you hit bugs on the current kernel version. I had to upgrade kernel of a box. It is a good experience and The following procedure is based… Continue reading Tips on Linux Kernel Upgrade
Many people agree that Linux kernel is pretty stable. It doesn’t crash pretty often. But there are times you hit a bug and It suddenly crash. In that case kdump is useful for investigating the reason. Kdump can be simply defined as Linux Kernel Crashdump Mechanism. It is used to gather diagnostic information during a… Continue reading Kdump – Kernel Crashdump
Why is this question is important for a DBA ? Actually the results are pretty surprising when you execute the query and see the last inserted date of a harddisk or a flashdisk. In another way, that information shows you the time you changed a faulty harddisk or flashdisk on the exadata. If you deleted… Continue reading When is the last time you changed a flashdisk or harddisk on Exadata ?
Extended statistics were introduced in the oracle cost based optimized beginning with 11g. They are used to gather information on the correlated columns. For example there is a correlation between the “county” and “city” column of a table. Number of distinct values over these columns can not be calculated by multiplying the NDV (number of… Continue reading Extended Statistics