Re: BUG #15287: postgres_fdw: the "WHERE date_trunc('day', dt) = 'YYYY-MM-DD' does not push to remote.

>>>>> "Tom" == Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

Tom> Alternatively, if postgres_fdw could know which functions don't
Tom> really pay attention to their input collation, it could skip this
Tom> check for those functions. But that's not an easy thing to fix
Tom> either.

Wild idea: we have quite a few functions (e.g. date_trunc, date_part,
timezone, encode, decode, make_timestamptz, plus various extension
functions such as in pgcrypto) that take a "text" parameter which is
nothing more than a poor-man's enum, or otherwise represents something
which isn't actually free text. Perhaps these should use "name" instead,
or in some cases an enum type?

(or in the case of date_trunc and extract, maybe they need to be split
up into separate functions so that we can properly distinguish the
immutable from the mutable cases)

--
Andrew (irc:RhodiumToad)