On 17/10/2013 00:06, Merlin Moncure wrote:
That being said, I do think it might be better behavior (and still
technically correct per the documentation) if volatile query
expressions were force-evaluated.
This sounds reasonable for a "yes or no" case like this, but wouldn't it raise the question of
how many times the function should be evaluated?
What if the query looked more like this:
with tt_created as
(
select fn_new_item(foo) as item
from some_huge_table
)
select item
from tt_created
limit 10
Should the CTE be calculated in its entirety, running the function for every row in some_huge_table? Or should it run at most 10 times?
Which is desired would depend on the situation, but there's no real way to indicate in the syntax.
--
Rowan Collins
[IMSoP]
