Re: Why we don't want hints Was: Slow count(*) again...

Shaun Thomas <sthomas@peak6.com>

From: Shaun Thomas <sthomas@peak6.com>
To: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: Josh Berkus <josh@agliodbs.com>, Robert Haas <robertmhaas@gmail.com>, "pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
Date: 2011-02-10T17:30:46Z
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@peak6.com

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