Re: REDO LOG Concepts

Hi Daniel,

I did not try for other processes. But will the rm command in OS command queue? Is there any posibility to rollback the delete when the instance is open? And if at all it is possible will the commited transactions be reclaimed?

Deepak

On 5/17/07, Daniel W. Fink <daniel.fink_at_optimaldba.com> wrote:
>
> This occurs as at least one of the Oracle processes (LGWR, others?) still
> has the redo log open. You can rm it and it will 'disappear' from the file
> list, but as it is still open by LGWR. so when the log buffer is flushed and
> written by LGWR, it is written to the file that LGWR still has open. Once
> you shutdown the instance, LGWR terminates and lets go of the file, which is
> then 'officially' rmed. When the instance is restarted, the process(es)
> attempt to open the file, but cannot as it has been deleted.
>
> --
> Daniel Fink
>
> Oracle Performance, Diagnosis and Training
>
> OptimalDBA http://www.optimaldba.com
> Oracle Blog http://optimaldba.blogspot.com
>
> Join me at Miracle Scotland DB Forum!http://www.miracleltd.com/index.asp?page=167&page2=343
>
>
>
> DBA Deepak wrote:
>
> Hi All,
>
> As we know when we issue a COMMIT the log buffer content is flushed to the
> online redo log file before the "Commit complete" status is returned to the
> user. Please correct me if I am wrong.
>
> I have the following scenario...
>
> SQL> select member from v$logfile;
>
> MEMBER
> --------------------------------------------------------------------------------
>
> /u04/oradata/BIDWDB01/redo03.log
> /u04/oradata/BIDWDB01/redo02.log
> /u04/oradata/BIDWDB01/redo01.log
>
> SQL> !rm /u04/oradata/BIDWDB01/redo01.log
>
> SQL> !rm /u04/oradata/BIDWDB01/redo02.log
>
> SQL> !rm /u04/oradata/BIDWDB01/redo03.log
>
>
> SQL> connect scott/oracle
> Connected.
> SQL> update emp set ename=ename;
>
> 14 rows updated.
>
> SQL> commit;
>
> Commit complete.
>
> SQL> commit;
>
> Commit complete.
>
> SQL> conn / as sysdba
> Connected.
> SQL> shutdown immediate
> Database closed.
> Database dismounted.
> ORACLE instance shut down.
>
>
> SQL> startup
> ORACLE instance started.
>
> Total System Global Area 4479516672 bytes
> Fixed Size 1984504 bytes
> Variable Size 905975816 bytes
> Database Buffers 3556769792 bytes
> Redo Buffers 14786560 bytes
> Database mounted.
> ORA-00313: open failed for members of log group 1 of thread 1
> ORA-00312: online log 1 thread 1: '/u04/oradata/BIDWDB01/redo01.log'
>
>
>
>
>
> -----------------------
>
> My question is even after deleting all the online redo log files how did
> Oracle returned the Commit complete status to the user? What happened to the
> log buffer data flush?
>
> I am using 10.2.0.2 on Solaris 9 (64-bit)
>
>
> Regards,
>
> Deepak
>
>
>

-- 
Regards,

Deepak
Oracle DBA

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