Sometime, there is no OEM around to check the explain plan of a specific statement. We need a bare way to do the job. Here are examples to check the explain plan.SQL> explain plan FOR SELECT COUNT(*) FROM SH.SALES;Explained.SQL> set linesize 120;SQL> select * from table(dbms_xplan.display);Since the result is too wide to be displayed well, […]
OS administrator might claim the candidate disks prepared for you to install ASM are newly created and very clean. But if they are not, then, you will meet failure during installing ASM, and never know the reason.Maybe you can mount the ASM diskgroup through ASMCA if you decide to ignore the error, but you will still […]
ORA-12537 Overview There’re several possible causes to raise ORA-12537: Incorrect File Permission White or Black List ORA-12537 Caused by Incorrect File Permission Incorrect file permission will prevent connections from being established. That is to say, potentially successful connections will be interrupted by ORA-12537 due to wrong file permissions, specifically, the execution permission. As a result, […]
After installing grid infrastructure, you will have Oracle Clusterware, also called Cluster Ready Service, CRS controls all Oracle cluster components as resources, and manages the dependencies among resources, so it can coordinate their start and stop priority.Restart a database server will bring CRS up (ohasd), once CRS is up, CRS will arrange the resources to […]
After a fast-start failover, the broker will try to reinstate the standby database (former primary database) for sustaining data guard architecture. While reinstating, the broker startup only one node of RAC to perform transportation service, which will remain the other node of RAC in mount state. Even when the primary role has been switched back, […]
Before enabling fast-start failover in data guard broker, the only required precondition is enabling Flashback Database. But before enabling Flashback Database, you must enable Flash Recovery Area (FRA). The other configurations that are not required but they might make your fast-start failover go smoothly.Set FastStartFailoverTarget on a database which is the target database to be switched […]
Since a fast-start failover (automatic failover) could become a false failover when the observer or the standby database cannot connect to the primary database within a specific time, which may cost the database to lose some transactions followed by reinstating or recreating the standby database (the former primary database).Therefore, it could be a bad idea […]
There are two major restrictions must be considered before you add a datafile to a tablespace. One is about the number limit of datafiles, the other is about the size limit of a datafile.The number limit of datafilesDB_FILES in spfileYou can regards the initialization parameter as a soft limit, if you add a datafile and […]
In some cases, you would like to change the default startup option of srvctl other than OPEN, for example, after duplicating a standby database, it needs to go to MOUNT state to prevent users from accessing. For convenience, you can set the default open option to mount. Then, every time you restart your standby database, […]
In the default behavior, if session A wants to see session B’s results, he must be waiting for session B to commit his transaction explicitly or an implicit commit is triggered.Implicit commits will happened under normal session terminations:Gracefully exit.To exit a program will notify database to disconnect from this session and then close the program. […]
