Обсуждение: LANGUAGE sql functions don't use the custom plan logic

Hi,

I recently was forcfully reminded that sql functions don't use the
plancache.c infrastructure. I was sort of aware of that, but I didn't
think far enough ahead that that also implies we'll not use custom plans
for statements with parameters when it'd be helpful.

That's imo quite the trap. Should we document it somewhere?

Greetings,

Andres Freund

Andres Freund <andres@anarazel.de> writes:
> I recently was forcfully reminded that sql functions don't use the
> plancache.c infrastructure. I was sort of aware of that, but I didn't
> think far enough ahead that that also implies we'll not use custom plans
> for statements with parameters when it'd be helpful.

There's a whole lot of ways in which the current implementation of
SQL-language functions leaves things to be desired.  What did you
run into exactly?
        regards, tom lane

On 2015-07-10 09:52:30 -0400, Tom Lane wrote:
> There's a whole lot of ways in which the current implementation of
> SQL-language functions leaves things to be desired.

Yea.

> What did you run into exactly?

A generic plan was used on a partitioned table.  Normally the function
could be inlined so that wasn't noticeable, but in one case it
wasn't... It's confusing if all invocations of the same function are
reasonably fast, but one, with the numerically same values passed down,
isn't.

Andres