Re: GUC parameter cursors_tuple_fraction

"Hell, Robert" <Robert(dot)Hell(at)fabasoft(dot)com> writes:
> This patch adds a GUC parameter for tuple_fraction of cursors (discussed
> earlier here:
> http://archives.postgresql.org/pgsql-performance/2008-04/msg00018.php).
> By setting this parameter the planner's favor to use fast-start plans
> for cursors can be affected.

Applied with some documentation cleanup, and also care for the behavior
at the range endpoints 0 and 1. A user expecting it to act like a
simple fraction would have been quite surprised at the endpoints
(see the header comments for grouping_planner).

regards, tom lane