[prev in list] [next in list] [prev in thread] [next in thread] 

List:       postgresql-general
Subject:    [HACKERS] OSCON fallout - Compressed Annealing optimizer
From:       Chris Browne <cbbrowne () acm ! org>
Date:       2006-07-31 22:25:30
Message-ID: 60k65tjtt1.fsf_-_ () dba2 ! int ! libertyrms ! com
[Download RAW message or body]

Robert Hansen did a talk at OSCON on a compressed annealing framework
called Djinni: <http://sixdemonbag.org/Djinni/>

It's a framework to use compressed annealing (a derivative of
simulated annealing) for finding approximate solutions to NP-complete
problems such as the TSP with time windows.  Note that while Djinni is
implemented in C++, it already supports embedding via SWIG, and has a
C wrapper and is accessible from other languages.  And it's
BSD-licensed...

This has the potential to be an alternative to the present use of GEQO
for query optimization for cases of large joins (e.g. - involving
large numbers of tables).

On the one hand, I'm somewhat suited to looking at this in that I have
the operations research background to know what they're talking about.
On the other hand, I'm not familiar with the optimizer, nor do I deal
with sorts of cases with so many joins that this would be worthwhile.

I've bounced a ToDo entry over to Bruce, and am making sure this is
documented here on pgsql.hackers so that a web search can readily find
it in the future...
-- 
"cbbrowne","@","cbbrowne.com"
http://www3.sympatico.ca/cbbrowne/
"It is far from complete, but it  should explain enough that you don't
just stare at your sendmail.cf file like a deer staring at an oncoming
truck."  -- David Charlap

---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
       choose an index scan if your joining column's datatypes do not
       match
[prev in list] [next in list] [prev in thread] [next in thread]