On Sunday 08 June 2008 19:07:21 Gregory Stark wrote: > "Joshua D. Drake" <[EMAIL PROTECTED]> writes: > > On Fri, 2008-06-06 at 20:19 -0400, Tom Lane wrote: > >> Robert Treat <[EMAIL PROTECTED]> writes: > >> > >> Actually, the reason it's still 10 is that the effort expended to get it > >> changed has been *ZERO*. I keep asking for someone to make some > >> measurements, do some benchmarking, anything to make a plausible case > >> for a specific higher value as being a reasonable place to set it. > >> > >> The silence has been deafening. > > > > Not surprising really. It is a simple adjustment to make and it also is > > easy to spot when its a problem. However it is not trivial to test for > > (in terms of time and effort). I know 10 is wrong and so do you. If you > > don't I am curious why I see so many posts from you saying, "Your > > estimates are off, what is your default_statistics_target?" with yet > > even more responses saying, "Uhh 10." > > Ah, but we only ever hear about the cases where it's wrong of course. In > other words even if we raised it to some optimal value we would still have > precisely the same experience of seeing only posts on list about it being > insufficient. >
The slipside to this is that we're not trying to find the perfect setting, we're just trying to determine a number that will cause more benefit than harm compared to the number we have now. While I am sure there are cases where 100 is too low as well, I cannot recall ever having seen someone suggest lowering the default_stats_target to something less than 100. (I know sit back and wait for someone to comb the archives, just to find that 1 time). -- Robert Treat Build A Brighter LAMP :: Linux Apache {middleware} PostgreSQL -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers