Leave it to the guru to inspire confidence. It's actually not that bad
for me. In this case, I can control the loads into the warehouse. So,
disables is not a big deal... I can make sure nothing comes in during
the exchange/export.
The catch you didn't mention is that I found not only do you have to
leave the constraint in NOVALIDATE mode, I've had to use RELY as well.
Otherwise, I found a peculiar "bug" where some queries cause the
optimizer to drop the ball.
This is in 8.1.7.0... and from what I get from Oracle, they have no
idea and it's probably not fixed.
Thanks... from what you've stated, I'll assume you HAVE NOT done
this yourself on a large database. Not the answer I was looking for.
john.
"Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote in message news:<aomb57$1tu$3$8300dec7_at_news.demon.co.uk>...
> John,
>
> It's slightly worse than you think.
>
> Despite comments by Daniel, some data
> warehouse systems do run without constraints
> (or constraints which are DISABLE RELY)
> in order to get the optimizer to know how the
> data hangs together, without the overhead of
> maintaining indexes. BUT they are data warehouse
> which are only subject to batch loads, and the batch
> code is supposed to prove that the constraints are
> not needed.
>
> --
> Regards
>
> Jonathan Lewis
> http://www.jlcomp.demon.co.uk
>
Received on Tue Oct 29 2002 - 11:15:11 CST
