| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> |
| Cc: | "David E(dot) Wheeler" <david(at)justatheory(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Does Type Have = Operator? |
| Date: | 2016-05-11 16:54:14 |
| Message-ID: | CA+TgmoZwVHh7ijmV=wLjRGizGH0kmY5ocVCnxBGrFqze0F6wQg@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Tue, May 10, 2016 at 9:16 PM, David G. Johnston
<david(dot)g(dot)johnston(at)gmail(dot)com> wrote:
> Brute force: you'd have to query pg_amop and note the absence of a row with
> a btree (maybe hash too...) family strategy 3 (1 for hash) [equality] where
> the left and right types are the same and match the type in question.
The core system uses this kind of thing to find equality operators in
a number of cases.
We often assume that the operator which implements equality for the
type's default btree operator class is the canonical one for some
purpose. Ditto for the default hash operator class.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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