> Tomas Vondra <tv@xxxxxxxx> writes: >> I've been thinking about this and I think it might be improved. If I >> understand the logic corretly, it says 'use half of the histogram bin >> size'. But the value > >> #define DEFAULT_RANGE_INEQ_SEL 0.005 > >> says it's always 0.5%, which is not not true if STATISTICS TARGET is not >> 100. This could actually yield 10x more precise estimates when the >> STATISTICS TARGET is set to 1000. > > Huh? The default estimates are completely unrelated to the size of the > histogram, and certainly unrelated to the default size of the > histogram. We use those estimates when we don't have relevant stats. > It's pure wishful thinking to suppose that changing the statistics > target would have any impact on what the estimate ought to be in such > a case. Ooops, sorry for the crazy gibberish I've posted earlier. I thought those default estimates work a somehow different and haven't checked that in the code. The proposed 'optimization' obviously does not make any sense. regards Tomas -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
