RE: Disable logging in tablespace vs using hidden parameter _disable_logging

Juan,

Setting NOLOGGING on a tablespace does not, in and of itself, do anything. That setting becomes the default for any segments created in the tablespace. Further, NOLOGGING does not have an effect on all operations. Actually, it's quite a small subset of operations that NOLOGGING will have an effect on. Some of these include: index creation, index rebuild, insert /*+ APPEND */, just to name a few. It's important to understand NOLOGGING and how it works, so that you may understand the recovery implications. Blocks loaded using NOLOGGING will NOT be recoverable till a backup is taken after the NOLOGGING operation is complete. More details on NOLOGGING can be found at: http://www.jlcomp.demon.co.uk/faq/nologging.html

_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."

-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Juan Carlos Reyes
Pacheco
Sent: Thursday, February 02, 2006 1:40 PM
To: Li-Shan Cheng
Cc: oracle-l_at_freelists.org
Subject: Re: Disable logging in tablespace vs using hidden parameter


_disable_logging


HI Li, thanks I know that, I RTFM,

It is an open question about how to get the _disable_logging effect
without using that parameter.

What I'm asking is  about applying no logging to all tablespaces before
import?
Compared to setting _disable_logging?
I don't know if some one knows about improvements.
For example
"setting nologgin to all tablespace I saved 1% of time, but I set this
other parameter too, etc.."
And any other comment about reducing logging activity without using the


_disable_logging parameter.

:)
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