Archived redo logs shorter than originals

Giganews Newsgroups
Subject: Archived redo logs shorter than originals
Posted by:  David Hollenberg (dholl…@marten.isi.edu)
Date: 7 Oct 2005

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?

I have a TAR open with Oracle about this, but haven't gotten any
useful information so far.

Dave

--

David Hollenberg    dholl…@NOmosisSPAM.org  http://www.mosis.org/
MOSIS Service                            Voice 310-448-8704
Information Sciences Institute          FAX  310-823-5624

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