X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id 5FC70D853A for ; Wed, 14 Sep 2005 00:20:43 -0300 (ADT) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 67886-03 for ; Wed, 14 Sep 2005 03:20:20 +0000 (GMT) Received: from xproxy.gmail.com (xproxy.gmail.com [66.249.82.200]) by svr1.postgresql.org (Postfix) with ESMTP id 69AA6D70BC for ; Wed, 14 Sep 2005 00:20:19 -0300 (ADT) Received: by xproxy.gmail.com with SMTP id h28so68224wxd for ; Tue, 13 Sep 2005 20:20:19 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:references; b=frIOsZ5FTajXRlotera0I/JZWGhm7PawyPA0Km16RCzNvgrfxAEOlxNBNZdwDW62hLoVnj3GJWGeEhwEdq0qacivsO56vTE+OG2xCZLtsbXmlktp3S2APDDBt91BATbZdOcU76cDKVBEEomuU70I0aSUJai7cQ2eZogYe+Y5yuU= Received: by 10.70.131.13 with SMTP id e13mr116560wxd; Tue, 13 Sep 2005 20:20:19 -0700 (PDT) Received: by 10.70.18.3 with HTTP; Tue, 13 Sep 2005 20:20:19 -0700 (PDT) Message-ID: Date: Wed, 14 Sep 2005 00:20:19 -0300 From: Pryscila B Guttoski Reply-To: pryscila.lista@gmail.com To: Tom Lane Subject: Re: About method of PostgreSQL's Optimizer Cc: Neil Conway , pgsql-performance@postgresql.org In-Reply-To: <28318.1126664818@sss.pgh.pa.us> Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_29428_5839971.1126668019297" References: <43275DCA.7040006@samurai.com> <28318.1126664818@sss.pgh.pa.us> X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=1.404 required=5 tests=[AWL=-0.509, HTML_30_40=0.056, HTML_MESSAGE=0.001, RCVD_BY_IP=0.024, RCVD_IN_BL_SPAMCOP_NET=1.832] X-Spam-Level: * X-Archive-Number: 200509/184 X-Sequence-Number: 14492 ------=_Part_29428_5839971.1126668019297 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Hi guys, I really appreciate your suggestions abouts papers, specially this one:=20 http://citeseer.csail.mit.edu/371707.html I found some answers on it, like this: Q: Why the main query planner uses a nearly-exhaustive search? A: (Page 20 - 4.2.2) ... up to about ten joins, dynamic programming is=20 preferred over the randomized algorithms because it is faster and it=20 guarantees finding the optimal plan. For larger queries, the situation is= =20 reversed, and despite the probabilistic nature of the randomized algorithms= ,=20 their efficiency makes them the algorithms of choice.=20 Also in this paper, there is something about the A* algorithm very=20 interesting for my research. I have one more question, sorry for doing it on this list, but only here I= =20 had answers... Does anybody hear anything about using PDDL ("Planning Domain Definition=20 Language") for query optimization? []'s, Pryscila On 9/13/05, Tom Lane wrote: >=20 > Neil Conway writes: > > Pryscila B Guttoski wrote: > >> On my master course, I'm studying the PostgreSQL's optimizer. > >> I don't know if anyone in this list have been participated from the > >> PostgreSQL's Optimizer development, but maybe someone can help me on= =20 > this > >> question. >=20 > > pgsql-hackers might be more appropriate. >=20 > AFAIK the basic code goes back to Berkeley days. Elein might possibly > remember something about it, but no one else that's on the project now > was involved then. The right place to look would be in the Berkeley > project's publications: >=20 > http://db.cs.berkeley.edu//papers/ >=20 > I agree with Neil's point that it's a spiritual descendant of System R > and there's plenty of material about that in the general database > literature. >=20 > regards, tom lane > ------=_Part_29428_5839971.1126668019297 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Hi guys,

I really appreciate your suggestions abouts papers, specially this one: http://citeseer.csail.mi= t.edu/371707.html

I found some answers on it, like this:

Q: Why the main query planner uses a nearly-exhaustive search?
A: (Page 20 - 4.2.2) ... up to about ten joins, dynamic programming is preferred over the randomized algorithms because it is faster and it guarantees finding the optimal plan. For larger queries, the situation is reversed, and despite the probabilistic nature of the randomized algorithms, their efficiency makes them the algorithms of choice.

Also in this paper, there is something about the A* algorithm very interest= ing for my research.

I have one more question, sorry for doing it on this list, but only here I = had answers...
Does anybody hear anything about using PDDL ("Planning Domain Definiti= on Language") for query optimization?

[]'s,
Pryscila

On 9/13/05, Tom Lane <tgl@sss.pgh.pa.us= > wrote:
Neil Conway <neilc@samurai.com&= gt; writes:
> Pryscila B Guttoski wrote:
>> On my master cou= rse, I'm studying the PostgreSQL's optimizer.
>> I don't know if a= nyone in this list have been participated from the
>> PostgreSQL's Optimizer development, but maybe someone can help= me on this
>> question.

> pgsql-hackers might be more a= ppropriate.

AFAIK the basic code goes back to Berkeley days. &n= bsp;Elein might possibly
remember something about it, but no one else that's on the project now<= br>was involved then.  The right place to look would be in the Be= rkeley
project's publications:

http://db.cs.berkeley.edu//papers/

I agree with Neil's point tha= t it's a spiritual descendant of System R
and there's plenty of material= about that in the general database
literature.

   = ;            &n= bsp;        regards, tom lane

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