On Friday 05 December 2008 00:05:34 Robert Haas wrote: > On Thu, Nov 27, 2008 at 6:46 PM, Gregory Stark <[EMAIL PROTECTED]> wrote: > >> ANALYZE with default_statistics_target set to 10 takes 13 s. With > >> 100, 92 s. With 1000, 289 s. > > > > That is interesting. It would also be interesting to total up the time it > > takes to run EXPLAIN (without ANALYZE) for a large number of queries. >
I wonder if we'd see anything dramatically different using PREPARE... > OK, I did this. I actually tried 10 .. 100 in increments of 10 and > then 100 ... 1000 in increments of 50, for 7 different queries of > varying complexity (but all generally similar, including all of them > having LIMIT 100 as is typical for this database). I planned each > query 100 times with each default_statistics_target. The results were > somewhat underwhelming. > The one thing this test seems to overlook is at what point do we see diminshing returns from increasing dst. I think the way to do this would be to plot dst setting vs. query time; Robert, do you think you could modify your test to measure prepare time and then execute time over a series of runs? -- Robert Treat Conjecture: http://www.xzilla.net Consulting: http://www.omniti.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
