Re: Ghost Data
- From: Julio Aguilar-Chang <jachang@xxxxxxxx>
- To: Brandon.Allen@xxxxxxxxxxx
- Date: Tue, 30 Jun 2009 17:12:05 -0600
Brandon,
Please explain "it had a bunch of data from other database tables in
it". Is this other data actual "application" data, not just data
dictionary data?
Julio.
Allen, Brandon wrote:
I'm starting a new thread on this specific topic to avoid high jacking
the other one. Reading about this "ghost data" reminds me of a
surprising discovery I made a few months ago but had forgotten about
until today.
I created a brand new tablespace with a new datafile, created one
table in the new tablespace and inserted one row. When I ran
"strings" on the datafile, I only saw the instance name and tablespace
name -- so far, so good. Then I forced a checkpoint to write the data
out to the file and was surprised to find that when I looked at the
datafile with "strings" again, it had a bunch of data from other
database tables in it.
Is this normal, known behavior? Does Oracle just copy data from other
blocks of the database into the new file as buffer space to fill it
up? I duplicated this on 8.1.7.3 and 10.2.0.4.
Thanks,
Brandon
*From:* oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *Michael Wehrle
*Sent:* Tuesday, June 30, 2009 1:45 PM
*To:* Mathias Magnusson; oracle-l
*Subject:* Re: Quickest Way To Recreate a Database
Mathias, Oracle explains what this ghost data is here...
http://www.oracle.com/technology/deploy/security/database-security/transparent-data-encryption/tde_faq.html#A15032
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Julio Aguilar-Chang
Geophysics Group, EES-17
Los Alamos National Laboratory
jachang@xxxxxxxx
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(505) 665-3687 - fax
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