| From: | Shaun Thomas <sthomas(at)peak6(dot)com> |
|---|---|
| To: | Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov> |
| Cc: | Josh Berkus <josh(at)agliodbs(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Why we don't want hints Was: Slow count(*) again... |
| Date: | 2011-02-10 17:30:46 |
| Message-ID: | 4D5420C6.3030608@peak6.com |
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| Lists: | pgsql-hackers pgsql-performance |
On 02/10/2011 11:21 AM, Kevin Grittner wrote:
> Something like this syntax?:
>
> JOIN WITH (correlation_factor=0.3)
I was thinking more:
JOIN foo_tab USING (foo_id) WITH (COST=50)
or something, to exploit the hooks that already exist for functions, for
example. But it's still an interesting concept. Tell the optimizer what
you want and how the data is really related in cases where it's wrong,
and let it figure out the best path.
--
Shaun Thomas
OptionsHouse | 141 W. Jackson Blvd. | Suite 800 | Chicago IL, 60604
312-676-8870
sthomas(at)peak6(dot)com
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