Re: PostgreSQL and Linux 2.6 kernel.

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От Simon Riggs
Тема Re: PostgreSQL and Linux 2.6 kernel.
Дата
Msg-id KGEFLMPJFBNNLNOOOPLGKEPACHAA.simon@2ndquadrant.com
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Ответ на Re: PostgreSQL and Linux 2.6 kernel.  (Josh Berkus <josh@agliodbs.com>)
Список pgsql-performance
>Josh Berkus
> > Treating the optimizer as a black box is something I'm very
> used to from
> > other RDBMS. My question is, how can you explicitly
> re-write a query now
> > to "improve" it? If there's no way of manipulating queries without
> > actually re-writing the optimizer, we're now in a position where we
> > aren't able to diagnose when the optimizer isn't working
> effectively.
>
> Well, there is ... all of the various query cost parameters.

They are very blunt instruments for such a delicate task.

Surely someone of your experience might have benefit from something
more?

My feeling is, I would, though I want those tools as *a developer*
rather than for tuning specific queries for people, which is always so
sensitive to upgrades etc.

> But, ultimately, improvements on the planner are still
> bottlenecked by having
> only one developer actually hacking the changes.
>

Do we have a clear list of optimizations we'd like to be working on?

The TODO items aren't very related to specific optimizations...

The only ones I was aware of was deferred subselect evaluation for
DBT-3.



...sounds like there's more to discuss here, so I'll duck out now and
get back to my current project...

Best Regards, Simon Riggs


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