Re: Range Types, constructors, and the type system - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Range Types, constructors, and the type system
Date
Msg-id 11379.1309100807@sss.pgh.pa.us
Whole thread Raw
In response to Re: Range Types, constructors, and the type system  (Darren Duncan <darren@darrenduncan.net>)
Responses Re: Range Types, constructors, and the type system
List pgsql-hackers
Darren Duncan <darren@darrenduncan.net> writes:
> I believe that the best general solution here is for every ordered base type to 
> just have a single total order, which is always used with that type in any 
> generic order-sensitive operation, including any ranges defined over it, or any 
> ORDER BY or any <,>,etc.

We've spent years and blood on making sure that Postgres could support
multiple orderings for any datatype; and there are plenty of natural
examples for the usefulness of that.  So I'm not at all impressed by
any line of reasoning that starts out by baldly throwing that away.

> When we want to have some other "native" ordering for an existing type, such as 
> when we want to use a different text collation, we do this by creating a *new 
> base type*,

Nope.  This has all sorts of problems that you're conveniently ignoring,
beginning with the need to duplicate all of the infrastructure for the
type (such as non-ordering-related operators), and then moving into
difficulties arising from added ambiguity as to which operator is meant.
        regards, tom lane


pgsql-hackers by date:

Previous
From: Markus Wanner
Date:
Subject: Re: POSIX question
Next
From: Simon Riggs
Date:
Subject: Re: ALTER TABLE lock strength reduction patch is unsafe