On Fri, 21 May 2010, Richard Yen wrote:
> Any ideas why the query planner chooses a different query plan when using prepared statements?
This is a FAQ. Preparing a statement makes Postgres create a plan, without
knowing the values that you will plug in, so it will not be as optimal as
if the values were available. The whole idea is to avoid the planning cost
each time the query is executed, but if your data is unusual it can
result in worse plans.
Matthew
--
Existence is a convenient concept to designate all of the files that an
executable program can potentially process. -- Fortran77 standard
