Re: Question about ARCHIVELOG mode

"agis" <stag_at_hq.acn.gr> wrote in message news:<cjjjq5$88f$1_at_ulysses.noc.ntua.gr>...
> "Ed Stevens" <nospam_at_noway.nohow> wrote in message
> news:o1kql01sauvc19d71e1nl1cg5bo4c6qm6p_at_4ax.com...
> > On 1 Oct 2004 01:29:20 -0700, pyzhykea_at_belhard.com (Eugene Pyzhyk)
> > wrote:
> >
> >>Hello all!
> >>
> >>Can you help me ?
> >>
> >>Does anybody know, may I start Oracle Server in ARCHIVELOG mode and
> >>perform redo logs archiving in manual mode (only when I want to
> >>archive it). Or automatic redo logs archiving must be enabled for
> >>correct Oracle Server functioning ?
> >>
> >>Thank you!
> >>
> >>Eugene Pyzhyk
> >
> > If you are manually archiveing, what do you think Oracle is going to
> > do when all of the on-line archive logs are full and you aren't
> > Johnny-on-the-spot to issue your manual archive command? In short,
> > why would you even consider manual archiving?
>
>
> This is not a posibility ...
>
> 1) There are not online archive logs Archive logs are archived redo logs
>
> 2) Redo log is a cycling mechanism in simple words. In manual archive mode
> it will operate the same way as in noarchivelog mode !!! until a command
> archives the logs !!!!
> (snip)

This last statement of yours is complete nonsense, utter rubbish and fully irresponsible. Obviously you've never tried this on a real database, else you'd realise your database comes to a grinding halt until the redo logs are archived manually. This is a similar situation to an archive log destination filling to capacity; the database stops all processing until the archive mechanism can continue its activity. Since you have no automatic archive mechanism running you'll see this stop much more quickly as your database will only process data for X*(log switch time), X being the number of redo log groups and (log switch time) begin the interval between redo log switches. If you're following Oracle's guidelines you should have no less than 15 minutes between log switches, and, for 3 log groups, your database would stop all processing after a period of 45 minutes.

Archivelog mode is designed to PRESERVE redo log entries, meaning your redo logs MUST be archived before they are overwritten. NOARCHIVELOG mode means you don't care about long-term recovery and overwrites occur after you've cycled through your redo log groups whether you've saved the old logs or not. They don't work the same way, nor was that the intent. To insist they function in the manner you describe is lunacy.

David Fitzjarrell Received on Fri Oct 01 2004 - 16:39:47 CDT