Robert Haas <robertmh...@gmail.com> writes: > On Tue, May 19, 2020 at 11:32 AM Tom Lane <t...@sss.pgh.pa.us> wrote: >> Before we go much further on this, we should have some proof >> that there's actually material benefit to be gained. I spent some >> time just now trying to relax the AS restriction by ripping out >> postfix ops, and the results were not too promising.
> I came to similar conclusions a couple of years ago: > https://www.postgresql.org/message-id/ca+tgmoyzpvt7uihjwgktytivhhlncp0ylavcoipe-lyg3w2...@mail.gmail.com Ah, right. > What I proposed at the time was creating a new category of keywords. Might work. My main concern would be if we have to forbid those keywords as column names --- for words like "year", in particular, that'd be a disaster. If the net effect is only that they can't be AS-less col labels, it won't break any cases that worked before. Our existing four-way keyword classification is not something that was handed down on stone tablets. I wonder whether postfix-ectomy changes the situation enough that a complete rethinking would be helpful. I also continue to think that more lookahead and token-merging would be interesting to pursue. It'd hardly surprise anybody if the token pair "character varying" were always treated as a type name, for instance. Anyway, the bottom-line conclusion remains the same: let's make sure we know what we'd do after getting rid of postfix ops, before we do that. regards, tom lane
