RE: performance impact of archivelog
- From: Flado <vandreev@xxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Tue, 18 Nov 2008 15:05:26 +0100
Here's a discussion on archivelog vs. noarchivelog mode:
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:421219463156
It is quite long and somewhat noisy - but I just read most of it so let me
summarize:
A big (negative) performance impact of switching to archivelog mode is
likely to come from the sudden importance of the NOLOGGING attribute.
If you:
a) do lots of direct-path inserts,
AND
b) your segments are LOGGING
Then switching to archivelog mode will cause a huge increase in redo
generation: basically, your direct-path inserts will now be fully logged
(where they previously weren't).
So if you do not have this setup, and you have taken measures to prevent the
obvious problems (waits for log buffer space, log file switch completion
(archiving needed), and so on) you should not notice the transition.
<quote>
> I always see these things discussed in terms of "more" but never in terms
> of "how much".
>
</quote>
What do you expect to see? The performance impact of archivelog varies,
depending on too many things, from 0 (in most cases - see above) to infinity
(when your archive log destination fills up). That's why the only true
statement one can make about it - aside from "it depends(tm)" - is "possibly
more".
Cheers!
Flado
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