Oracle Starter Library 1102 error handling

Oracle
First, ask questions



There are times in the real world when you encounter a ORA-01102 error when you try to start a database with startup. We can switch to Oracle users under UNIX, and perform Oerr Ora 1102 to see a brief description of 1102, as follows:



Rp2$[/home/ora2]oerr Ora 1102

01102, 00000, "Cannot mount Database in EXCLUSIVE mode"

*cause:some Other instance has the database mounted exclusive or shared.

*action:shutdown other instance or mount in a compatible mode



It must be a little confusing to read this 1102 short explanation because it has some misleading nature. I will then analyze the causes of the problem and give a solution.



Second, analysis of the reasons



When you start the database encountered 1102 error, the previous database down operation is not normally completed, or due to some exceptions to Oracle in the operating system, the residual memory structure, Pmon, such as a few processes still exist and other reasons that Oracle mistakenly believe that instance is still running, so the library does not start, specifically for the following reasons:



1, Pmon, Smon, LWGW and DBWR These background processes still exist

2, Oracle opened up the shared memory has not been released

3, "lk<sid>" and "sgadef<sid>.dbf" These two files for the lock memory exist.



Iii. Problem-solving



Knowing the reason, the solution is much simpler, the way is as follows:



1, look at the "lk<sid>" and "sgadef<sid>.dbf" These two files are not exist, if there is to delete them.

ORACLE$CD $ORACLE _home/dbs



Oracle$ls-l sgadef<sid>.dbf

If it exists, delete it.

ORACLE$RM sgadef<sid>.dbf



Oracle$ls-l lk<sid>

If it exists, delete it.

ORACLE$RM lk<sid>



2, see if there is a background process exists



Oracle$ps-ef | grep Ora_ | grep $ORACLE _sid



If there are pmon of these background processes, kill-9 it off.

Oracle$kill-9 PID



3, look at Oracle's shared memory segment and signal set (semaphores) is there still



1) Clearing the shared memory segment



Oracle$ipcs-m--show, see Owner is Oracle User's

Oracle$ipcrm-m <Shared_Memory_ID>



2) Clear Signal set



Oracle$ipcs-s--show, see Owner is Oracle User's

Oracle$ipcrm-s <Semaphore_ID>



Four, should be no problem, try it again ^ ^