Re: GSoC idea - Simulated annealing to search for query plans

On 02/26/2015 01:59 PM, Grzegorz Parka wrote:
> Dear Hackers,
>
> I'm Grzegorz Parka, BSc Engineer of Technical Physics and student of
> Computer Science at WUT, Poland. Last year I've been a bit into
> evolutionary algorithms and during my research I found out about GEQO in
> Postgres. I also found out that there are plans to try a different
> attempt to find optimal query plans and thought it could be a good thing
> to use it as a project for GSoC.
>
> I'm interested in one of old TODO items related to the optimizer -
> 'Consider compressed annealing to search for query plans'. I believe
> this would be potentially beneficial to Postgres to check if such a
> heuristic could really choose better query plans than GEQO does. Judging
> by the results that simulated annealing gives on the travelling salesman
> problem, it looks like a simpler and potentially more effective way of
> combinatorial optimization.
>
> As deliverables of such a project I would provide a simple
> implementation of basic simulated annealing optimizer and some form of
> quantitative comparison with GEQO.

You might look at the earlier attempt to make the GEQO replacement
"pluggable". That project failed to complete sufficiently to be a
feature though, but it did enough to show that our current GEQO
implementation was suboptimal.

I'm currently searching for this project ... it was a GSOC project, but
I think before they required posting to Google Code.

--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com