Re: About method of PostgreSQL's Optimizer

Hi guys,

I really appreciate your suggestions abouts papers, specially this one:
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
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
interesting 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 Definition
Language") for query optimization?

[]'s,
Pryscila

On 9/13/05, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> Neil Conway <neilc(at)samurai(dot)com> 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
> this
> >> question.
>
> > pgsql-hackers might be more appropriate.
>
> 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:
>
> http://db.cs.berkeley.edu//papers/
>
> 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.
>
> regards, tom lane
>