Re: getting the most of out multi-core systems for repeated complex SELECT statements

Mark,

you could try gevel module to get structure of GIST index and look if 
items distributed more or less homogenous (see different levels). 
You can visualize index like http://www.sai.msu.su/~megera/wiki/Rtree_Index
Also, if your searches are neighbourhood searches, them you could try knn, available
in 9.1 development version.


Oleg

On Thu, 3 Feb 2011, Mark Stosberg wrote:

>
> Each night we run over a 100,000 "saved searches" against PostgreSQL
> 9.0.x. These are all complex SELECTs using "cube" functions to perform a
> geo-spatial search to help people find adoptable pets at shelters.
>
> All of our machines in development in production have at least 2 cores
> in them, and I'm wondering about the best way to maximally engage all
> the processors.
>
> Now we simply run the searches in serial. I realize PostgreSQL may be
> taking advantage of the multiple cores some in this arrangement, but I'm
> seeking advice about the possibility and methods for running the
> searches in parallel.
>
> One naive I approach I considered was to use parallel cron scripts. One
> would run the "odd" searches and the other would run the "even"
> searches. This would be easy to implement, but perhaps there is a better
> way.  To those who have covered this area already, what's the best way
> to put multiple cores to use when running repeated SELECTs with PostgreSQL?
>
> Thanks!
>
>    Mark
>
>
>

 	Regards,
 		Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83