On Mon, 08 May 2006 19:37:37 -0400, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: > Jeffrey Tenny <jeffrey.tenny@xxxxxxxxxxx> 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@xxxxxxxxxxxxxx : 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 : : +---------------------------------------+-----------------+
