On 4 June 2016 at 14:10, Christophe Pettus <x...@thebuild.com> wrote: > Something I've noticed frequently is that HashAggregate will, especially if > the children are Append with one of the nodes a non-seqscan, estimate 200 > rows rather than a calculated vlaue. Where is that value coming from? The > statistics target, a hardwired constant, or something else?
Most likely from DEFAULT_NUM_DISTINCT in selfuncs.h. This is the fallback, when nothing else can be used. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers