Raj, The alert log shows the log switching, which is the indicator to how much redo has been generated. Another method is to see this figure from v$log_history. The objective is to identify the rate of redo switch and therefore, the rate of redo generation. The original poster asked how to estimate the archive log generatoin and I answered that.
However, a slip was the inclusion of log_checkpoints_to_alert, which is admittedly not necessary. However, the content of the post was factually correct. Kirti, in a private mail, was kind enough to let me know of the possible confusion and I appreciate that. Hope that clarifies the response. Arup ----- Original Message ----- To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Tuesday, January 21, 2003 10:50 AM > > 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@ho To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> > tmail.com> cc: > Sent by: Subject: Re: from Non-Archive-Mode to Archive-Mode > root@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 > > ----- Original Message ----- > To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> > Sent: Friday, January 17, 2003 1:25 PM > > > > > 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@ho To: Multiple recipients of > list ORACLE-L <[EMAIL PROTECTED]> > > tmail.com> cc: > > > Sent by: Subject: Re: from > Non-Archive-Mode to Archive-Mode > > root@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" <[EMAIL PROTECTED]> > > 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: [EMAIL PROTECTED] > > 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: [EMAIL PROTECTED] (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.net -- Author: Arup Nanda INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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).
