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Home -> Community -> Mailing Lists -> Oracle-L -> Re: from Non-Archive-Mode to Archive-Mode
Arup,
My initial reaction was that you were suggesting setting the parameter to know the frequency of your log switches. But now to clearly understand your point of view, and for my curiousity, how does one derive the amount of redo log generated in bytes using the SCN Numbers?
Thanks
Raj
"Arup Nanda"
<arupnanda_at_ho To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
tmail.com> cc:
Sent by: Subject: Re: from Non-Archive-Mode to Archive-Mode
root_at_fatcity.
com
January 17,
2003 05:54 PM
Please
respond to
ORACLE-L
Raj,
I'm afraid I don't understand. Was that incorrect in some way? The alert log will contain information when the redo logs switch, e.g.
Thread 1 advanced to log sequence 38451
Current log# 1 seq# 38451 mem# 0: /x12/oradata/IDW1/redo01a.dbf
Current log# 1 seq# 38451 mem# 1: /x22/oradata/IDW1/redo01rba.dbf
Fri Jan 17 17:46:49 2003
Completed checkpoint up to RBA [0x9633.2.10], SCN: 0x0000.4f7c86d7
Completed checkpoint up to RBA [0x9632.2.10], SCN: 0x0000.4f7c86d5
Fri Jan 17 17:46:50 2003
Beginning log switch checkpoint up to RBA [0x9634.2.10], SCN:
0x0000.4f7c86d9
Thread 1 advanced to log sequence 38452
Current log# 3 seq# 38452 mem# 0: /x12/oradata/IDW1/redo03a.dbf
Current log# 3 seq# 38452 mem# 1: /x22/oradata/IDW1/redo03b.dbf
This will help identify the frequency of log switch and an indicator to the
amount of redo generated. The question was how to estimate the amount of
archive log generation and that was one way. So, is that wrong? Please do
correct me if you think so. Of course the information can be readily
obtained from v$log_history; but then again, that's another way, not the
only way.
Arup
>
> Arup,
>
> From your past replies to the list, I am surprised to hear you say this.
> "If you have placed the init.ora parameter log_checkpoints_to_alert set
to
> TRUE, then your alert log file will have lines when the redo log group
> switch fom one to the other."
>
> Regards
> Raj
>
>
>
>
>
> "Arup Nanda"
> <arupnanda_at_ho To: Multiple recipients of
list ORACLE-L <ORACLE-L_at_fatcity.com>
> tmail.com> cc:
> Sent by: Subject: Re: from
Non-Archive-Mode to Archive-Mode
> root_at_fatcity.
> com
>
>
> January 17,
> 2003 09:35 AM
> Please
> respond to
> ORACLE-L
>
>
>
>
>
>
> Murat,
>
> The estimate of amount of space for archive logs come from your redo log
> switch. If you have placed the init.ora parameter
log_checkpoints_to_alert
> set to TRUE, then your alert log file will have lines when the redo log
> group switch fom one to the other. That will give you a rough idea of the
> time it takes to fill up a redo log. If you are using archiving, the redo
> log has to be written to disk. In any one given day, you can then
calculate
> the archive log generation.
>
> Then comes how you want to back it up and clean up the space. If you have
a
> process running that will scan for archive logs; back them to tape and
then
> delete it, then you have to figure out how often this process runs and
how
> much archive log stays on the disk before getting deleted.
>
> Changing the log mode of the tablespace level does not change teh redo
log
> genration in most cases. If you define a tablespace or an object as
> nologging, only a few operations like ALTER TABLE .. PARTITION, ALTER
INDEX
> REBUILD, direct load are not logged, all others are. And in any case the
> system tables are always logged.
>
> HTH.
>
> Arup
>
> ----- Original Message -----
> To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>
> Sent: Friday, January 17, 2003 5:08 AM
>
>
> > Hi,
> >
> > how can I calculate/estimate the extra disk space I'll need if I
> > change the log mode from non-archive-mode to archive-mode. I want to
> change
> > the log mode of all my objects. Do I need to do this one-by-one or is
it
> > enough if I change the log mode of my tablesapces?
> >
> > Thanks in advance
> >
> > Murat
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: INET: Rajesh.Rao_at_jpmchase.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- 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 Tue Jan 21 2003 - 09:50:05 CST
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