Re: Question about ARCHIVELOG mode

From: Ms. D.H. Harvey <qq45_at_liverpool.ac.uk>
Date: 1 Oct 2004 14:01:42 GMT
Message-ID: <cjjo06$bjt$1@news.liv.ac.uk>

,agis <stag_at_hq.acn.gr> wrote:

: "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 !!!!

Mmmmm - I don't think so! When you are in archivelog mode you cannot reuse a redo log until its contents have been archived no matter waht archive mode you are in. Lets say you have 3 redo logs A B and C, are in archivelog mode and manually archiving.
  Redo log A fills, move onto redo log B.   Redo log B fills so go onto redo log C.   Now redo log C fills - you are unable to cycle back to/reuse redo log A   as it has not yet been archived. Your database stops/hangs waiting for   this to happen!!! It has to otherwise what's the point of archivelogging?

As Ed said 'why would you even consider manual archiving?'?

Helen Received on Fri Oct 01 2004 - 09:01:42 CDT