On Wed, 2012-11-21 at 15:27 +0000, Simon Riggs wrote:
> It would be useful if we issued a NOTICE when an ambiguity is
> introduced, rather than when using it.
>
> Like Bison's reporting of reduce conflicts.
This brings up a very important point, which is that a lot of the code
is frozen in applications yet invisible at DDL time. So we have to be
careful that DDL changes have a reasonable impact on the ability to
continue to compile and execute the previously-working SQL received from
the applications.
In other words, as I said in another reply, we want to avoid cases where
something seemingly innocuous (like creating a function) causes
previously-working SQL to fail due to ambiguity.
As Tom said, detecting the ambiguity at DDL time is not easy, so I'm not
suggesting that. And I know that creating a function can already cause
previously-working SQL to fail. I'm just saying we should be careful of
these situations and not make them more likely than necessary.
Regards,Jeff Davis