Re: Query Slow in 10g, runs very fast in 8i

EscVector wrote:
> Jonathan Lewis wrote:

<snip>
> > What's the rationale behind that suggestion ?
>
>
> I think you said it best: "The first (and only) rule of optimization
> is: "Avoid unnecessary effort".

There are of course 3 words in that sentence and the middle one is rather important. It isn't a synonym for "make no effort". Or in the words of the scientist "Make it as simple as possible, *but no simpler*"

> This no brain approach avoids people effort. If it doesn't work, add
> brain.

If I wanted to avoid human effort I'd throw machine effort at it, in the form of the Oracle provided tuning tools or from a third party. Changing parameters because once upon a time they helped unrelated problems is not really the most appropriate approach that I have ever seen. I've twice had to visit my doctors this year. They have about 5 minutes to diagnose what is up with me. I'd be mortified if they merely prescribed something because it had helped someone else on another occasion - especially if it waa something that made drastic alterations to my biological state.

> The other simple answer is I've had it work in the past when we had to
> make very quick adjustments to things we couldn't test or spend time
> researching and that couldn't be changed.

Why change anything if you can't test it. If the org can't afford to make an informed decision why make any change at all? After all it isn't worth the cost of testing.

> This no brain approach avoids people effort which is usually the most
> costly component to any effort. To something while your doing the real
> thing. That's the rational.

Isn't it more sensible to do nothing while you are doing the real thing? I mean the suggestion you make *could* be an extraordinarily bad suggestion reducing elapsed time from 11 hours to 11 days...

Niall Received on Fri Jan 05 2007 - 15:52:56 CST