Re: performance question (something to do w/ parameterized

[Klint Gore <kg(at)kgb(dot)une(dot)edu(dot)au>]

On Mon, 08 May 2006 19:37:37 -0400, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Jeffrey Tenny <jeffrey(dot)tenny(at)comcast(dot)net> writes:
> > The server was already running with random_page_cost=2 today for all tests, because of
> > the mods I've made to improve other problem queries in the past (my settings noted below, and
> > before in another msg on this topic).
> 
> > So to nail this particular query something additional is required (even lower random_page_cost?).
> > What's a good value for slower processors/memory and database in memory?
> 
> If you're pretty sure the database will always be RAM-resident, then 1.0
> is the theoretically correct value.

Would it be possible to craft a set of queries on specific data that
could advise a reasonable value for random_page_cost?

What sort of data distribution and query type would be heavily dependant
on random_page_cost?  i.e. randomness of the data, size of the data
compared to physical memory.

klint.

+---------------------------------------+-----------------+
: Klint Gore                            : "Non rhyming    :
: EMail   : kg(at)kgb(dot)une(dot)edu(dot)au           :  slang - the    :
: Snail   : A.B.R.I.                    :  possibilities  :
: Mail      University of New England   :  are useless"   :
:           Armidale NSW 2351 Australia :     L.J.J.      :
: Fax     : +61 2 6772 5376             :                 :
+---------------------------------------+-----------------+