Hi Deepak
You will likey find that your database when you succeed in opening it does
not show the transaction as successful. This is because the commit caused
the lgwr to write your activity to the redo logs however the dbw has not at
this time written your transaction to the datafile. This means that when you
issued the shutfown immediate, the redo log items are not necessarily
written to the datafiles. There is no requirement for Oracle to do this, I
suspect that they do.
The concepts guide is not clear on this with an immediate shutdown,
however if it was a shutdown abort your tranaction would in effect be rolled
back(not a true roll back) as in the abort Oracle waits until the restart to
apply or not apply information in the redo files.
------------------------------
*From:* DBA Deepak [mailto:oracle.tutorials@xxxxxxxxx]
*Sent:* Thursday, 17 May 2007 01:08 PM
*To:* daniel.fink@xxxxxxxxxxxxxx
*Cc:* oracle-l@xxxxxxxxxxxxx
*Subject:* 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@xxxxxxxxxxxxxx> 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
