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Home -> Community -> Mailing Lists -> Oracle-L -> RE: identify which logs are need to start recovery
Hi, Rahul,
Unfortunately, there is no v$view. v$log_history also isn't a good
candidate - v$log_history data are stored in the controlfile, and
controlfile loss would make database unrecoverable (we know, this is not the
case).
My assumption is Oracle stores checkpoint SEQ# in the datafile header, as well as SCN, and for recovery purposes Oracle checks every datafile, takes minimum SEQ# and prompt us for this log.
The following command is used to dump file headers
alter session set events 'immediate trace name file_hdrs level 10';
The following is a small piece of dump, note thread:1 rba:(0xb6.6d.160) at the end - I strongly believe 0xb6 is SEQ# and thread:1 is thread number of redo log, required for recovery. Archived log SEQ# will be this number minus one.
DATA FILE #10:
(name #13) /u02/oradata/simplydb/simply.dbf
creation size=12800 block size=4096 status=0xe head=13 tail=13 dup=1
tablespace 9, index=10 krfil=10 prev_file=0
unrecoverable scn: 0x0000.00000000 11/21/2000 10:54:54
Checkpoint cnt:1139 scn: 0x0000.00283091 03/29/2001 09:32:28
Stop scn: 0xffff.ffffffff 03/22/2001 13:00:14
Creation Checkpointed at scn: 0x0000.0001d187 11/16/2000 15:37:16
thread:1 rba:(0xb6.6d.160)
I'm not absolutely sure, this is correct, but looks like for me.
Best regards,
Vadim Gorbounov
Oracle DBA
-----Original Message-----
Sent: Thursday, March 29, 2001 3:19 AM
To: Multiple recipients of list ORACLE-L
Lisa/List,
when we restore a datafile from a backup, oracle will check the change# in
the header of the datafile
and will try to match it with the one in the controlfile, correct ? that's
how oracle will know that the file
is out-of-sync, now oracle will prompt from the change# as well as the log
sequence number to apply !!
from where does it get the log sequence number ? is it sotred in each
datafile ? or oralce queries it
from v$log_history ?
Rahul
> ----------
> From: Koivu, Lisa[SMTP:lkoivu_at_qode.com]
> Sent: Thursday, March 29, 2001 12:02 PM
> To: 'ORACLE-L_at_fatcity.com'; 'rahul_at_ratelindo.co.id'
> Subject: RE: identify which logs are need to start recovery
>
> Hi Rahul,
>
> I'm not sure if there's a v$ view that will tell you, I remember looking
> for this myself.
> However if you initiate recovery it will ask for the appropriate arclog,
> and you can always cancel out. During testing, I found that it will ask
> for every single one since the backup set from which you restored your
> datafile, regardless of whether or not it needs it (in this case, the
> datafile that was lost didn't contain any tables that had changed since
> the last backup. Go figure).
>
> HTH
>
> Lisa Rutland Koivu
> Oracle Database Administrator
> lkoivu_at_qode.com
>
> NeoMedia
>
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>
> -----Original Message-----
> From: Rahul [ mailto:rahul_at_ratelindo.co.id]
> Sent: Wednesday, March 28, 2001 11:13 PM
> To: Multiple recipients of list ORACLE-L
> Subject: identify which logs are need to start recovery
>
>
> usually i keep 2-3 previous archived logs, after switching and starting
> the
> hotbackup...
>
> but is there a v$ view to show which logs are needed to start the recovery
> ?
>
> TIA
>
> Rahul
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Rahul
> INET: rahul_at_ratelindo.co.id
>
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-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Rahul INET: rahul_at_ratelindo.co.id Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Vadim Gorbounov INET: vgorbounov_at_simplyengineering.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Thu Mar 29 2001 - 09:22:40 CST
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