Re: REDO LOG Concepts
- From: "DBA Deepak" <oracle.tutorials@xxxxxxxxx>
- To: "Alexander Fatkulin" <afatkulin@xxxxxxxxx>
- Date: Thu, 17 May 2007 12:46:50 +0530
Hi Alexander,
I do not think UNIX removes the directory entry immediately. Otherwise how
would it access the REDO logs by their paths.
What might be happening is UNIX is marking it as deleted (may be using a
flag or so). Please do correct me if am wrong.
Deepak
On 5/17/07, Alexander Fatkulin <afatkulin@xxxxxxxxx> wrote:
Deepak,
As others have already pointed out - you actually didn't delete
anything. You just unlinked a directory entry in a file system. File
is still "there" and is open by the LGWR.
Shutdown immediate is a clean shutdown (no instance recovery is
required after it).
On 5/17/07, DBA Deepak <oracle.tutorials@xxxxxxxxx> 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
--
Alexander Fatkulin
--
Regards,
Deepak
Oracle DBA
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