From: | Bruce Momjian <bruce(at)momjian(dot)us> |
---|---|
To: | "David E(dot) Wheeler" <david(at)kineticode(dot)com> |
Cc: | Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: 8.4 release notes proof reading 1/2 |
Date: | 2009-03-28 14:24:10 |
Message-ID: | 200903281424.n2SEOAK05146@momjian.us |
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Lists: | pgsql-hackers |
David E. Wheeler wrote:
> On Mar 27, 2009, at 6:40 PM, Bruce Momjian wrote:
>
> > Thanks, text updated:
> >
> > While semi-joins merely replace existing IN joins, anti-joins
> > are a new capability for NOT EXISTS clauses (Tom) This improves
> > optimization possibilities.
>
> I'm not enough of a relational algebra geek to really understand what
> that means. Will there be a link or something to some documentation or
> even, *gasp*, a blog entry explaining what this means and why it's
> important?
Uh, not really; the optimizer stuff is usually quite vague and Tom
might end update removing it once he goes over the release note anyway
(he has in the past). I documented it because it is a user-visible
change, I think, becuase it might show up in EXPLAIN.
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
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