Re: [Review] Re: minor patch submission: CREATE CAST ... AS EXPLICIT

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Andres Freund <andres(at)2ndquadrant(dot)com>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, cedric(at)2ndquadrant(dot)com, pgsql-hackers(at)postgresql(dot)org, Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>
Subject: Re: [Review] Re: minor patch submission: CREATE CAST ... AS EXPLICIT
Date: 2013-06-24 13:55:22
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Andres Freund <andres(at)2ndquadrant(dot)com> writes:
> What about simply not using a keyword at that location at all? Something
> like the attached hack?

"Hack" is much too polite a word for that. This will for example fail
to respect the difference between quoted and unquoted words. If the
argument for this patch is to make the syntax more regular and less
surprising, I hardly think that we should add surprise of a different

Generally speaking, I agree with Robert's objection. The patch in
itself adds only one unnecessary keyword, which probably wouldn't be
noticeable, but the argument for it implies that we should be willing
to add a lot more equally-unnecessary keywords, which I'm not. gram.o
is already about 10% of the entire postgres executable, which probably
goes far towards explaining why its inner loop always shows up high in
profiling: cache misses are routine. And the size of those tables is
at least linear in the number of keywords --- perhaps worse than linear,
I'm not sure. Adding a bunch of keywords *will* cost us in performance.
I'm not willing to pay that cost for something that adds neither
features nor spec compliance.

regards, tom lane

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