Re: what is the different?

Not entirely certain what benefits you get using the one approach over the other, given that even the "new" syntax won't produce an instantaneous archive file, so you'd still have to wait for a bit before it being safe to copy the archives.

Anyway: as far as I see it, Niall's right. Switch logfile can be done to any database (and will trigger a checkpoint); archive log current will only work on databases in archivelog mode. The subtler difference is that on a database in archivelog mode, with the Archiver proces enabled, 'switch logfile' will cause ARCH to do the archiving, but 'archive log current' will cause your *server process* to do the archiving.

So if the latter always produces an error, but the former does not, I'd suspect that ARCH had hung, or hadn't been enabled in the first place (ie, LOG_ARCHIVE_START or its 8i variants hasn't been set in the init.ora).

I usually get an error message when it's the other way round when the archive destination that ARCH is about to use (the default, or LOG_ARCHIVE_DEST is specified incorrectly) is one to which I don't have permissions (or which doesn't exist). 'Archive log current to <other destination>' will then correctly work, since I get to pick a directory to which I *do* have permissions.

Regards
HJR

--
=============================!!=============================
The views expressed are my own only, and definitely NOT those of Oracle
Corporation
=============================!!=============================


"Spencer" <spencerp_at_swbell.net> wrote in message
news:P0eQ6.438$My3.106492_at_nnrp3.sbc.net...


> in our hot backup scripts, we use the "archive log current" syntax to

> ensure that the current log file is archived.  prior to the introduction

> of this syntax, the script used the "switch logfile", and then waited for

> several minutes to give ARCH enough time to archive the log file,

> before continuing.

>

>  one place we use the the

> "Niall Litchfield" <niall.litchfield_at_dial.pipex.com> wrote in message

> news:3b114c75$0$15030$cc9e4d1f_at_news.dial.pipex.com...

> > alter system switch logfile switches between current online redo logs.

 It


> > (should) always work.

> >

> > alter system archive log current will archive the (current) redo log. It

> > thus requires all of the prerequisites for archiving redo logs.

> >

> > Most likely causes for the second command to fail

> >

> > 1. you are not in archivelog mode

> > 2. you have run out of space in your archive log destination.

> >

> > The error message in the alert log will tell you what the problem is.

> >

> > IMO you should also not usually need to issue the second command since

> > oracle will quite happily archive redo logs for you automatically.

> >

> >

> > --

> >

> > Niall Litchfield

> > Oracle DBA

> > Audit Commission UK

> > "Cheong" <leslie_hk_at_hotmail.com> wrote in message

> > news:3b113326_at_newsgate.imsbiz.com...

> > > Can anyone tell me what is the different of the following two commands

> > >

> > > alter system archive log current

> > > alter system switch logfile

> > >

> > > and why the first command always produce and error a message fail to

 arhive


> > > log ... in alert log file.

> > >

> > > Thanks in advance

> > >

> > > Antony

> > >

> > >

> >

> >

> >

>

>