Re: redo curiosity

From: Maureen English <maureen.english_at_alaska.edu>
Date: Fri, 19 Feb 2010 11:38:32 -0900
Message-ID: <4B7EF6C8.3050103_at_alaska.edu>

Decisions, decisions.... Do we want speed and fewer redo logs, or do we want to guarantee consistent queries?

If the behavior in 8i is to truncate, then our users shouldn't even notice the difference in behavior, but they may notice the difference in refresh times. On the other hand, the refreshes in the 10g database currently take about the same amount of time as the refreshes in the 8i database...and disk space isn't really an issue....

*I* want the refreshes to go faster and generate less redo, but I'm pretty sure that from a user point of view, the read-consistency is far more important.

For now, I'm leaving our nightly refreshes as they are.

Thanks to all who added their $.02 here!

• Maureen

Allen, Brandon wrote:
> No problem, I'm sure atomic_refresh=>false will make a big difference in performance and
> redo size, but just beware of the affect on read-consistency if you're refreshing multiple
> views and also the fact that anything that queries the MV during the refresh could get
> zero rows if it queries after the truncate, but before the new rows are inserted.
> MOS 553464.1 has more detail.
>
> Regards,
> Brandon
>

--
http://www.freelists.org/webpage/oracle-l

Received on Fri Feb 19 2010 - 14:38:32 CST