Re: Simple join optimized badly?

[Mark Kirkwood <markir@xxxxxxxxxxxxxxx>]

Craig A. James wrote:

> Perhaps you scanned past what I wrote a couple paragraphs farther down.  
> I'm going to repeat it because it's the KEY POINT I'm trying to make:
>
> Craig James wrote:
> > Now you might argue that function-cost needs to be added to the 
> > optimizer's arsenal of tricks.  And I'd agree with you: That WOULD be 
> > a better solution than hints.  But I need my problem solved TODAY, not 
> > next year.  Hints can help solve problems NOW that can be brought to 
> > the PG team's attention later, and in the mean time let me get my 
> > application to work.

True enough - but (aside from the fact that hints might take just as 
long to get into the development tree as cost-for-functions might take 
to write and put in...) there is a nasty side effect to adding hints - 
most of the raw material for optimizer improvement disappears (and hence 
optimizer improvement stalls)- why? simply that everyone then hints 
everything - welcome to the mess that Oracle are in (and seem to be 
trying to get out of recently)!

I understand that it is frustrating to not have the feature you need now 
 - but you could perhaps view it as a necessary part of the community 
development process - your need is the driver for optimizer improvement, 
and it can take time.

Now ISTM that hints "solve" the problem by removing the need any further 
optimizer improvement at all - by making *you* the optimizer. This is 
bad for those of us in the DSS world, where most ad-hoc tools do not 
provide the ability to add hints.

Cheers

Mark