Re: Simple join optimized badly?

Jonah H. Harris wrote:
> On Oct 08, 2006 07:05 PM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
> > Hints are used because the DBA thinks that they are smarter than
> > the optimizer; 99% of the time, they are wrong.
>
> That's a figure which I'm 100% sure cannot be backed up by fact.
>
> > Just try manually optimizing a complex query, you'll see -- with three
> > join types, several scan types, aggregates, bitmaps, [blah blah blah]
> > it's significantly more than a human can figure out accurately.
>
> Let me get this right... the optimizer is written by humans who know and
> can calculate the proper query plan and generate code to do the same;
> yet humans aren't smart enough to optimize the queries themselves? A bit
> of circular reasoning here?

I can do 100! on my computer, but can't do it in my head.

--
Bruce Momjian bruce(at)momjian(dot)us
EnterpriseDB http://www.enterprisedb.com

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