Steve Rogerson <steve.pg@xxxxxxxxxxxxxxxxx> writes: > The date is "today" at the time of writing. The table is analyzed, to pg > should "know" that date1 <= "today" hence there is no data beyond today. It doesn't seem to, given this: > -> Bitmap Index Scan on ctable_date1 (cost=0.00..22534.71 > rows=598419 width=0) (actual time=5.204..5.204 rows=37536 loops=1) > Index Cond: (date1 >= '2017-08-10'::date) You should try just "explain analyze select * from ctable c where c.date1 >= '2017-08-10'" to confirm that that row estimate is wrong in isolation, but it looks like it is off by more than 10X. > ctable has about 60,000,000 rows. So basically, the planner is estimating 1% selectivity for this condition, when the true figure is more like 0.0625%. I find this unsurprising if you're using the default statistics target of 100 --- that means that the accuracy of histogram-related predictions can't be expected to be any better than 1%. If you crank up the stats target (for this column, or the whole table, or globally) and re-analyze, the estimate should get better, and then you should get a better plan. regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
