Re: Sorry, but...

From: Mladen Gogala <>
Date: Tue, 10 Jan 2012 13:07:14 +0000 (UTC)
Message-ID: <>

On Mon, 09 Jan 2012 18:10:56 -0800, Noons wrote:

> Separate, control and contain the I/O loads. Without RAC. I can't afford
> it! ;-)

Motivation for two undo spaces is clear: you would want one small undo tablespace for OLTP loads and another, larger one, for reports. It wouldn't necessarily help with ORA-01555 because there isn't a natural separation of undo records. The only good solution would enable DBA to choose per table undo space and that would immensely complicate things. You cannot separate undo tablespaces by the load type. A table can be modified by an OLTP application and reported from by a report. Consistency would still need to be maintained, which means that the report can only see the changes committed before the query has started, including OLTP changes. That means that there can be no separation per load type, only per table separation. That might prove beneficial, but would probably immensely complicate coding and end up being largely unused because one undo tablespace is quite adequate.

Received on Tue Jan 10 2012 - 07:07:14 CST

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