On 23 June 2016 at 18:31, Robert Haas <robertmh...@gmail.com> wrote: > > Sure, but aggregating as early as possible will often have the effect > of dramatically reducing the number of tuples that have to pass > through upper levels of the plan tree, which seems it would frequently > far outweigh those considerations. >
Agreed I can imagine plans where a useful aggregation occurs before every join, so N > 2 is easily possible. -- Simon Riggs http://www.2ndQuadrant.com/ <http://www.2ndquadrant.com/> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
