RE: Global temporary tables with No logging
- From: "Goulet, Richard" <Richard.Goulet@xxxxxxxxxxx>
- To: <mrosenblum@xxxxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 8 Jun 2009 13:29:23 -0400
Michael,
I've been all over Metalink on the subject, and yes GTT's do
generate redo, for the purpose of allowing one to rollback to a
savepoint. But then again, all of the complaints, notes, etc... point
to versions of Oracle less than 10.2.0.2.0.
Dick Goulet
Senior Oracle DBA
PAREXEL International
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Michael Rosenblum
Sent: Monday, June 08, 2009 12:08 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: Global temporary tables with No logging
Unfortunately, operations against temporary tables DO have an impact on
the volume of generated logs - at least as far as I understand.
The problem is that temporary tables do generate rollback - and the
rollback is logged. So, temporary tables will generate some redo.
Just to summarize the rule of thumb (quoting Tom Kyte's "Expert Oracle
Database Architecture" - p.322 If you don't have it in paper, here is a
link:
http://books.google.com/books?id=TmPoYfpeJAUC&printsec=frontcover#PPA322
,M1 ):
* INSERT - little to no rollback/redo activity
* DELETE - the same amount of redo as normal table
* UPDATE - about half the redo of an UPDATE of a normal table.
Regards,
Michael Rosenblum
Dulcian Inc
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Goulet, Richard
Sent: Monday, June 08, 2009 3:10 PM
To: walid_alkaakati@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: RE: Global temporary tables with No logging
Importance: High
If these are global temp tables then their are not the
cause of your increased archive log activity. Global temp tables have a
default of the temp tablespace and are never logged. The reason is that
once a session using a global temp table ends the table drops all of
it's data & storage. Transaction preservation of global temps is per
their definition. Refer to :
http://download.oracle.com/docs/cd/B28359_01/server.111/b28286/statement
s_7002.htm#i2095331. It's fro 11g, but still applicable to 10g.
You can specify nologging with the "alter table"
command, but that can be overridden if the database has supplemental
logging turned on as in there exists a physical standby.
The biggest thing is to check with the application
developers of provider. Some apps like PeopleSoft create "temporary"
tables that are there to pass data between sessions in a batch job. If
that's so, your stuck with them. If not consider rebuilding them as
global temps.
Dick Goulet
Senior Oracle DBA
PARE XEL International
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of walid alkaakati
Sent: Monday, June 08, 2009 8:15 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: Global temporary tables with No logging
Hallo list,
i have an application that uses about 60 Temporary tables, the
problem is that each day we i have more than 500 Mb as an increase in
Archive logs.
How can i specify No Logging option for these Temporary tables ?
when i try i get a syntax error, also i have read in one blog that
Global temporary tables do Not Genrate Redo, so can some one please
clarify the truth ?
Thank you all !
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