Robert Haas <robertmhaas@gmail.com> writes:
> for estimate_worstcase_fraction. So, when computing the cost of a
> path, we'd compute our current expected-case estimate, and also a
> worst-case estimate, and then compute the final cost as:
There also was the idea for the executor to be able to handle alternate
plans and some heuristic to determine that the actual cost of running a
plan is much higher than what's been estimated, so much so as to switch
to starting from scratch with the other plan instead.
Regards,
--
Dimitri Fontaine
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support