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Re: Flush

From: Antoine BRUNEL <antoinebrunel.yahoo.fr_at_nospam.fr>
Date: Tue, 31 Aug 2004 22:47:39 +0200
Message-ID: <4134e3eb$0$28734$79c14f64@nan-newsreader-05.noos.net>


Hi from Paris
"Sybrand Bakker" <sybrandb_at_hccnet.nl> a écrit dans le message de news:l5iui0l13gc0lolar2p5k8jucidie9llgj_at_4ax.com...
> On Fri, 27 Aug 2004 09:37:52 -0400, Bill Van Dyk
> <trash_at_christian-horizons.org> wrote:
>
> >I am testing Ocopy for the purpose of backing up our Oracle database and
> > I'm confused by something. When I make some test entries into a
> >table, the Oracle data files appear to be unchanged. I assumed that the
> >data would eventually flush into the data files, after a few hours or
> >so. It's been two days, and still no sign that the data files have been
> >updated. (This is a test system with no other users accessing the
> >tables.) What gives? How long should it take before the new data is
> >written to the actual Oracle data files? Or is it determined by the
> >size of the buffers in the log?
>
> The data will be written to disk, as soon as the transaction is
> committed.

Wrong. Redo entries will be written into the current redo log files when the transaction is commited, but not necessarily into the datafiles....

in fact, DBWR behaviour depend on number of things, one of them is a 3 s timeout, upon which it will write dirty buffers into disks.... (if nothing else happen)

Anyway, on the windows system, datafiles (log and control files too) are being opened in exclusive mode, so you will not see the last modification time be changed unless you stop / restart the instance....

> >
> >The database is called doris. The only file that has changed, on that
> >drive, during the time I entered the test data, is
> >\oracle\ora81\network\doris.log.
> >
>
> Not sure what this log file is, it looks like sqlnet logging. Doesn't
> tell anything.
>
> >Second question: for a complete backup, do I copy the log files?
> You don't copy the online redo log file, you do copy the archived redo
> log files.
> And do
> >they require "Ocopy"? Am I correct in assuming that the Ocopy utility
> >is only required for the .dbf files-- the other Oracle files including
> >the *.log and *.ctl files-- can they be copied with a standard dos
> >command?
> No, you are not correct. The control files definitely need to be
> copied using OCOPY as they are written to all the time.
>
>
> Any harm in using Ocopy on them as well?
> No.

>
> >
> >Thanks.
>
> --
> Sybrand Bakker, Senior Oracle DBA
Received on Tue Aug 31 2004 - 15:47:39 CDT

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