On Mon, Feb 22, 2016 at 4:32 AM, Tomas Vondra <tomas.von...@2ndquadrant.com> wrote: > Firstly, we could clamp the join cardinality estimate to the size of > cartesian product, eliminating at least the most obvious over-estimates. > > Secondly, I think it'd be nice to somehow eliminate the sudden jumps in the > estimates - I'm not quite sure why need the three different formulas in > eqjoinsel_semi, so maybe we can get rid of some of them?
I don't have any particularly intelligent commentary on the second point right at the moment, but I emphatically agree with you on the first one. I've seen that problem a number of times and it seems completely ludicrous to me. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
