Re: record identical operator

From: Peter Geoghegan <pg(at)heroku(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Stephen Frost <sfrost(at)snowman(dot)net>, Kevin Grittner <kgrittn(at)ymail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: record identical operator
Date: 2013-10-03 18:28:04
Message-ID: CAM3SWZTd3ySc0fK6Q-DontF+ZD6BR01qz9o3=i3T7RXizWPVJQ@mail.gmail.com
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On Thu, Oct 3, 2013 at 10:53 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> The point I want to make here is that we have an existing precedent to
> use bitwise equality when we want to make sure that values are
> equivalent for all purposes, regardless of what opclass or whatever is
> in use. There are not a ton of those places but there are some.

Btree opclasses (which are of course special, per "35.14.6. System
Dependencies on Operator Classes") are restricted by the reflexive
law, which implies that bitwise equality is a stronger condition than
regularly equality. I'm inclined to agree that it isn't a big deal to
expose a bitwise equality operator.

We're talking about the possibility of being potentially overly eager
according to someone's definition about refreshing, not the opposite.
With reference to an actual case where this is possible, I don't think
this is astonishing, though I grant Stephen that that's aesthetic.

I also agree that an intermediate notion of equality isn't worth it.

--
Peter Geoghegan

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