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Re: Disable logging in tablespace vs using hidden parameter _disable_logging

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Thu, 2 Feb 2006 19:48:26 -0000
Message-ID: <02a001c62831$a23ca5f0$0200a8c0@Primary>

Just as a side note, unless things have change in recent versions, _disable_logging still does all the work of generating redo log.

The only change is that lgwr doesn't bother to write the buffer when called - basically bypassing the actual file-write call.

This means you still get redo latch activity, and checkpoints. Given the fact that lots of systems now have a workable buffer between the redo writer and the hardware, this means that _disable_logging may give you no appreciable benefit, unless you create MASSIVE redo log and avoid commits.

Regards

Jonathan Lewis

http://www.jlcomp.demon.co.uk/faq/ind_faq.html The Co-operative Oracle Users' FAQ

http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html Cost Based Oracle: Fundamentals

http://www.jlcomp.demon.co.uk/appearances.html Public Appearances - schedule updated 10th Jan 2006

_disable_logging, on the other hand, says "I don't care about this
database, don't do any logging, if the database crashes, it's worthless, game reset, start over." This is quite different from, and far more dangerous than, NOLOGGING operations.

Hope that helps,

-Mark

--
Mark J. Bobak
Senior Oracle Architect
ProQuest Information & Learning

"There are 10 types of people in the world:  Those who understand
binary, and those who don't."


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Received on Thu Feb 02 2006 - 13:48:26 CST

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