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@sss.pgh.pa.us> wrote: Neil Conway <neilc@samurai.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