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

From: "Greg Sabino Mullane" <greg(at)turnstep(dot)com>
To: 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 16:39:51
Message-ID: bfb6382ea377f627038537aa7f59b02f@biglumber.com (view raw or flat)
Thread:
Lists: pgsql-committerspgsql-hackers
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> Playing around with this a bit, I was easily able to get 2-second
> planing times on 15 table join, 6-second planning times on a 16 table
> join and 30-second planning times on a 17 table join.  This makes it
> hard to support raising the GEQO threshold, as most recently suggested
> by Greg Sabino Mullane here (and previously by me on an earlier
> thread):

What about 14? Could we at least raise it to 14? 1/2 :)

I'm worried this is going to get bogged down like so many of our
threads, where we worry about verified test cases and getting
things exactly right and end up not making any changes at all
(see also: random_page_cost). Robert, any ideas on a way to fix
this overall process problem, outside of this particular geqo
issue? (If we had a bug tracker, this would certainly be a place
to stick something like this).

- --
Greg Sabino Mullane greg(at)turnstep(dot)com
End Point Corporation
PGP Key: 0x14964AC8 200912011139
http://biglumber.com/x/web?pk=2529DF6AB8F79407E94445B4BC9B906714964AC8
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