Re: generate_series woes

On Mon, Apr 14, 2008 at 5:21 AM, Harald Fuchs <hari(dot)fuchs(at)googlemail(dot)com> wrote:
> I think there's something sub-optimal with generate_series.
> In the following, "documents" is a table with more than 120000 rows,
> vacuumed and analyzed before the queries.

everything is working exactly as intended. while it's obvious to you
that the generate series function returns a particular number of rows
based on your supplied inputs, it's not (yet) obvious to the planner.
your genser function supplies the hint the planner needs and it
adjusts the plan. most set returning functions (particularly
non-immutable ones) are not so easy to determine the # of rows from
the input parameters anyways.

merlin