Skip site navigation (1) Skip section navigation (2)

Re: Re: [COMMITTERS] pgsql: Rewrite GEQO`s gimme_tree function so that it always finds a

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Greg Sabino Mullane <greg(at)turnstep(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Re: [COMMITTERS] pgsql: Rewrite GEQO`s gimme_tree function so that it always finds a
Date: 2009-12-01 19:07:22
Message-ID: 5327.1259694442@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-committerspgsql-hackers
Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Tue, Dec 1, 2009 at 11:39 AM, Greg Sabino Mullane <greg(at)turnstep(dot)com> wrote:
>> What about 14? Could we at least raise it to 14? 1/2 :)

> I doubt we can raise it at all without lying to ourselves about the
> likely results of so doing.  The GEQO planning times are in the low
> double digits of milliseconds.  My apps typically have a budget of at
> most ~200 ms to plan and execute the query, and I'm not always
> operating on empty tables.

The reason this is a configurable parameter is so that people can tune
it to their own needs.  I think the current default fits all right with
our usual policy of being conservative about hardware requirements.

			regards, tom lane

In response to

Responses

pgsql-hackers by date

Next:From: Greg StarkDate: 2009-12-01 19:10:07
Subject: Re: Block-level CRC checks
Previous:From: Aidan Van DykDate: 2009-12-01 19:06:32
Subject: Re: Block-level CRC checks

pgsql-committers by date

Next:From: Tom LaneDate: 2009-12-01 21:00:24
Subject: pgsql: Teach the regular expression functions to do case-insensitive
Previous:From: Robert HaasDate: 2009-12-01 18:12:18
Subject: Re: Re: [COMMITTERS] pgsql: Rewrite GEQO`s gimme_tree function so that it always finds a

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group