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Home -> Community -> Usenet -> c.d.o.server -> Re: Online backup: Backup online redologs?
"Randall Roberts" <randall_at_filer.org.nospam> wrote in message
news:3b24df70_2_at_news.pcmagic.net...
> I use shutdown immediate. I only use shutdown abort if shutdown immediate
> fails. I've seen shutdown immediate hang a session and not shutdown the
> database.
True. It can happen... though it shouldn't happen every time (and doesn't sound as if it does).
>With server manager I can start another session and shutdown
> abort. With SQL*Plus I've gotten the message that the database is
shutting
> down, and I can't start a new session even as internal.
I've seen that too many times for it to be a coincidence! Personally, I find SQL*Plus as an administrative tool (especially in 8.1.5) too buggy to rely on, and switch to Server Manager every time I want to startup, shutdown or perform the other Privileged Actions. SQl*Plus is fine for everything else.
>In 9i we won't have
> server manager or internal. I guess the only recourse there will be to
stop
> the service at the OS level.
No. In 9i, you have a version of SQL*Plus that (allegedly) actually works (and I should mention that the SQL*Plus in 8.1.7 was heaps better at performing Privileged Actions). And you have, as you have always had since 8.0, the 'connect / as sysdba' syntax, allowing you access as a Privileged User. That's been the recommended replacement for 'internal' ever since Oracle 8.0 -and you're just discovering why! 'Connect / as sysdba' and 'connect internal' are functionally identical -both give you access to the database as user SYS with the SYDBA system privilege.
Regards
HJR
>
> Best!
>
> Randall
>
> Charles J. Fisher <cfisher_at_rhadmin.org> wrote in message
> news:Pine.LNX.4.33.0106100922500.13875-100000_at_galt.rhadmin.org...
> > On Fri, 8 Jun 2001, Ravi Sista wrote:
> >
> > > PS : I tend to agree with Howard on this one. I don't think the way
you
> > > shut the database down matters (as long as it is down, when you
started
> > > the cold backup) when it comes to the validity of your cold backups.
Any
> > > one else with an opinion on this one? Thanks in advance.
> >
> > Couchman has been wrong many times, but here are his comments from the
8i
> > OCP book:
> >
> > "Oracle uses SCNs in control files, datafile headers, and redo records.
> > Every redo log file has both a log sequence number and low and high SCN.
> > The low SCN records the lowest SCN recorded in the log file, while the
> > high SCN records the highest SCN in the log file. CKPT writes those
> > numbers to the datafiles and to the control file. The checkpoint number
is
> > also written to the redo log file. When the database starts, all
> > checkpoint sequence numbers in all datafiles, redo log files, and
control
> > files must match. If they do not, Oracle will not start, and you must
> > perform media recovery on your database to get the files synchronized
and
> > in a consistent state." (p. 669)
> >
> > This seems to imply to me that interrupting an in-flight checkpoint with
a
> > shutdown abort can be deadly.
> >
> > In an apparent contradiction, he goes on to say:
> >
> > "A point was made earlier that SMON will perform instance recovery if it
> > detects that the datafiles are not synchronized. Recall that part of the
> > work done in a checkpoint is to write the SCN to datafile headers and
copy
> > data in the buffer cache and log buffer to their respective disk files.
> > This process synchronizes all Oracle files. If the instance crashes,
these
> > files will not be synchronized because Oracle did not have the
opportunity
> > to synchronize them before the instance failed. SMON will synchronize
them
> > for you automatically." (p. 678)
> >
> > To me, it is unclear where out-of-phase checkpoint information requires
> > instance recovery (SMON) or media recovery.
> >
>
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