On Wed, Feb 8, 2012 at 7:54 PM, Peter van Hardenberg <pvh@xxxxxx> wrote: > On Wed, Feb 8, 2012 at 6:47 PM, Peter van Hardenberg <pvh@xxxxxx> wrote: >> On Wed, Feb 8, 2012 at 6:28 PM, Scott Marlowe <scott.marlowe@xxxxxxxxx> wrote: >>> On Wed, Feb 8, 2012 at 6:45 PM, Peter van Hardenberg <pvh@xxxxxx> wrote: >>>> That said, I have access to a very large fleet in which to can collect >>>> data so I'm all ears for suggestions about how to measure and would >>>> gladly share the results with the list. >>> >>> I wonder if some kind of script that grabbed random queries and ran >>> them with explain analyze and various random_page_cost to see when >>> they switched and which plans are faster would work? >> >> We aren't exactly in a position where we can adjust random_page_cost >> on our users' databases arbitrarily to see what breaks. That would >> be... irresponsible of us. >> > > Oh, of course we could do this on the session, but executing > potentially expensive queries would still be unneighborly. > > Perhaps another way to think of this problem would be that we want to > find queries where the cost estimate is inaccurate. Yeah, have a script the user runs for you heroku guys in their spare time to see what queries are using the most time and then to jangle the random_page_cost while running them to get an idea what's faster and why. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
