| From: | Michael Paquier <michael(dot)paquier(at)gmail(dot)com> |
|---|---|
| To: | Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Peter Geoghegan <pg(at)bowt(dot)ie>, Robert Haas <robertmhaas(at)gmail(dot)com>, "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>, Greg Stark <stark(at)mit(dot)edu>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: 64-bit queryId? |
| Date: | 2017-10-03 01:09:38 |
| Message-ID: | CAB7nPqS7kSWTMRH7+bDJs3+vx0k4CRF0Aptie2BmeN7B3Jv9vg@mail.gmail.com |
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On Tue, Oct 3, 2017 at 9:07 AM, Alexander Korotkov
<a(dot)korotkov(at)postgrespro(dot)ru> wrote:
> +1,
> I see 3 options there:
> 1) Drop high-order bit, as you proposed.
> 2) Allow negative queryIds.
> 3) Implement unsigned 64-type.
>
> #1 causes minor loss of precision which looks rather insignificant in given
> context.
> #2 might be rather unexpected for users whose previously had non-negative
> queryIds. Changing queryId from 32-bit to 64-bit itself might require some
> adoption from monitoring software. But queryIds are user-visible, and
> negative queryIds would look rather nonlogical.
Per the principal of least astonishment perhaps:
https://en.wikipedia.org/wiki/Principle_of_least_astonishment
Negative values tend to be considered as error codes as well.
> #3 would be attaching hard and long-term problem by insufficient reason.
> Thus, #1 looks like most harmless solution.
In this case going for #1 looks like the safest bet.
--
Michael
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