On Wed, Jan 6, 2016 at 12:08 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
konstantin knizhnik <k.knizhnik@postgrespro.ru> writes: > 1. The cost compared in grouping_planner doesn't take in account price of get_authorized_users - it is not changed when I am altering function cost. Is it correct behavior?
The general problem of accounting for tlist eval cost is not handled very well now, but especially not with respect to the idea that different paths might have different tlist costs. I'm working on an upper-planner rewrite which should make this better, or at least make it practical to make it better.
Hmm... Besides costing it would be nice to postpone calculation of expensive tlist functions after LIMIT.