Re: DG convert to snapshot DB problem????
Date: Thu, 18 Aug 2011 18:17:46 +0200
Message-ID: <CAL6WDh3HDrRhLo1sxdG_36C2S74p03aX=ihnr8qdSHsbk1-Qzg_at_mail.gmail.com>
Hi,
that's the crucial difference of a snapshot standby - redo is NOT applied to it. As the name says, it's a snapshot of the current primary in a certain point in time so applying the redo on that would destroy it's purpose (hence step one in the conversion - stop redo apply). To have redo applied and therefore always the current state as in the primary and the database open in the same time, active data guard is used - but has to be licensed separately.
To sum up:
redo applied, database not open -> normal data guard
redo not applied, database open as snapshot of a certain point in time
-> snapshot standby
redo applied, database open and always the current state of the
primary -> active data guard
Best regards,
Robert
On Thu, Aug 18, 2011 at 6:00 PM, Robertson Lee - lerobe
<Lee.Robertson_at_acxiom.com> wrote:
> I am a REAL newcomer to this subject given that I am asking about it
> myself today, BUT.....
>
> Why are you trying to open your standby... ?
>
> From what I am reading after you have converted your database to
> snapshot standby you are done ?
>
> The syntax I saw in the article I was looking at was....
>
> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;
>
> (The statement includes the DISCONNECT FROM SESSION option so that Redo
> Apply runs in a background session.)
>
> Happy to be proved wrong by those who have been advising me though :-)
>
>
> -----Original Message-----
> From: oracle-l-bounce_at_freelists.org
> [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of dba1 mcc
> Sent: 18 August 2011 16:40
> To: oracle-l_at_freelists.org
> Cc: oracle-db-l_at_Groups.ITtoolbox.com
> Subject: DG convert to snapshot DB problem????
>
> we are doing DG version 11.1.0.7 "snapshot DB" practice. Currently we
> have problem can NOT change.
>
> ====== procedures ===
>
> SQL*Plus: Release 11.1.0.7.0 - Production on Thu Aug 18 11:28:17 2011
>
> Copyright (c) 1982, 2008, Oracle. All rights reserved.
>
> Connected to an idle instance.
>
> SQL> startup mount;
> ORACLE instance started.
>
> Total System Global Area 2087780352 bytes
> Fixed Size 2161272 bytes
> Variable Size 1795163528 bytes
> Database Buffers 251658240 bytes
> Redo Buffers 38797312 bytes
> Database mounted.
>
>
> SQL> alter database convert to snapshot standby;
>
> Database altered.
>
> SQL> alter database open;
> alter database open
> *
> ERROR at line 1:
> ORA-01507: database not mounted
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-- http://www.freelists.org/webpage/oracle-lReceived on Thu Aug 18 2011 - 11:17:46 CDT