Craig Ringer <craig@xxxxxxxxxxxxxxxxxxxxx> wrote: > Some of those tables are views composed of multiple unions, too, > by the looks of things. > > Doesn't the planner have some ... issues ... with estimation of > row counts on joins over unions? Or is my memory just more faulty > than usual? So far I can't tell if it's views with unions or (as I suspect) inheritance. The views and tables shown so far reference other objects not yet shown: core.inventory h.location h.actor However, I'm pretty sure that the problem is that the estimated row count explodes for no reason that I can see when the "Nested Loop Left Join" has an "Append" node from a parent table on the right. 28 rows joined to a 4 row append yields 51160 rows? 51160 rows joined to a 2 row append yields 203176856 rows? 203176856 rows joined to a 2 row append yields 806903677108 rows? Something seems funny with the math. I would have expected 28 times 4 times 2 times 2, equaling 448. Still higher than 15, but only by one order of magnitude -- where it might still make relatively sane plan choices. -Kevin -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
