From: | "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> |
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To: | Tijs van Dam <tijs(at)thalex(dot)com> |
Cc: | "pgsql-bugs(at)lists(dot)postgresql(dot)org" <pgsql-bugs(at)lists(dot)postgresql(dot)org> |
Subject: | Re: date/time special values incorrectly cached as constant in plpgsql |
Date: | 2020-10-17 15:35:32 |
Message-ID: | CAKFQuwYGbpZFHpRSbxsXouFDp5EQQJ6jHpN61dJCtoCjBHSKdQ@mail.gmail.com |
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On Sat, Oct 17, 2020 at 4:05 AM Tijs van Dam <tijs(at)thalex(dot)com> wrote:
> If no change is made to the parser, then I'd propose at least a big fat
> warning in section 8.5.1.4 that 'now', 'yesterday', 'today', and 'tomorrow'
> should only be used with the greatest caution, as these values will be
> converted to constants and then cached in unexpected places.
>
IMO, there really isn't anything surprising that these literal inputs end
up converted to constants, which are indeed cached in parts of the system
that utilize a cache, or are stored as the resultant literal instead of an
expression. That's how literal input values work. If I need something to
be dynamic I have to use a volatile function.
I've flagged this one for later consideration and may decide to write a
documentation patch at some point - but as the existing docs aren't wrong
and do cover this dynamic, if maybe not explicitly and thoroughly enough
for some readers, the effort/benefit calculation isn't that high for me.
David J.
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