Moin,
On 2019-10-20 16:27, Tom Lane wrote:
Tels <nospam-pg-ab...@bloodgate.com> writes:
On 2019-10-20 13:30, Andreas Karlsson wrote:
Agreed, this sounds like something useful to do since virtually all
strict functions cannot return NULL, especially the ones which are
used in tight loops. The main design issue seems to be to think up a
name for this new level of strictness which is not too confusing for
end users.
STRICT NONULL? That way you could do
CREATE FUNCTION f1 ... STRICT;
CREATE FUNCTION f2 ... STRICT NONULL;
CREATE FUNCTION f3 ... NONULL;
and the last wold throw "not implementet yet"? "NEVER RETURNS NULL"
would also ryme with the existing "RETURNS NULL ON NULL INPUT", but I
find the verbosity too high.
"RETURNS NOT NULL", perhaps? That'd have the advantage of not
requiring
any new keyword.
Hm, yes, that would be a good compromise on verbosity and align even
better the other "RETURNS ..." variants.
I'm a little bit skeptical of the actual value of adding this
additional
level of complexity, but I suppose we can't determine that reliably
without doing most of the work :-(
Maybe it would be possible to simulate the effect somehow? Or at least
we could try to find practical queries where the additional information
results in a much better plan if RETRUNS NOT NULL was set.
Best regards,
Tels
