Re: Function returning 2 columns evaluated twice when both columns are needed

Gerhard Wiesinger <lists(at)wiesinger(dot)com> writes:
> Since getSums() is a cursor and is complex and takes long time getSums
> should only be evaluated once. Is there a better solution available to
> get both columns from the function in the select?

You need a sub-select, along the lines of

SELECT
cur_date,
(gs).sum_m1,
(gs).sum_m2
FROM
(
SELECT
cur_date,
getSums(start_ts, stop_ts) AS gs
FROM
getDatesTimestamps($1, $2)
OFFSET 0
) AS ss
;

The OFFSET bit is a kluge, but is needed to keep the planner from
flattening the subquery and undoing your work.

regards, tom lane