Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: Archived redo logs shorter than originals

Re: Archived redo logs shorter than originals

From: Niall Litchfield <Niall.litchfield_at_dial.pipex.com>
Date: Sat, 08 Oct 2005 19:02:27 +0100
Message-ID: <43480864$0$11878$cc9e4d1f@news.dial.pipex.com>


David Hollenberg wrote:
> In Oracle 8.1.7.4 (on Solaris 8), archived redo log files were the
> same size as the original redo log file (i.e., archiving a 10 MB redo
> log file resulted in a 10 MB archived redo log file in the archive
> destination directories). In Oracle 10g release 2 (10.2.0.1.0 on
> Solaris 9), the archived redo log files are all significantly smaller
> than the originals. With 10 MB redo logs, the largest archived redo
> log file is about 8.8 MB and most of them are more like 7.5 MB (out of
> 150 total archived redo logs).
>
> We're archiving to 3 separate destinations and the archived redo
> logs are identical to each other in all 3 places (but different
> from the originals). I compared a few originals with their
> archived copies and other than a few bytes that differ
> in the first 1 KB, the files are identical until the archived
> copy ends (1-2 MB before the original file ends). This indicates
> to me that the reason for the size difference is NOT due to
> compression of the originals.
>
> Is there some change to the way redo log archiving works between 8i
> and 10g? Could there be some reason why log file switches would be
> happening well before the end of the redo log file?

redo has been redone in 10g (I think R1). Its possible that archiving might have changed as well. That said the most common reason for logs switching before they are full is because the log switch is scheduled (or coded in the app).

-- 
Niall Litchfield
Oracle DBA
http://www.niall.litchfield.dial.pipex.com
Received on Sat Oct 08 2005 - 13:02:27 CDT

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US