Re: Removing pg_migrator limitations

Andrew Dunstan <andrew@dunslane.net>

From: Andrew Dunstan <andrew@dunslane.net>
To: Bruce Momjian <bruce@momjian.us>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Greg Stark <gsstark@mit.edu>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: 2009-12-24T01:30:23Z
Lists: pgsql-hackers

Bruce Momjian wrote:
> I wasn't aware enum ordering is something we tried to maintain.
> One issue is that we are not supporting the addition of enum values even
> for people who don't care about the ordering of enums (which I bet might
> be the majority.)
>   

The ordering of enums is defined and to be relied on and I think it's 
absolutely unacceptable not to be able to rely on the ordering.

We should never be in a position where the values returned by 
enum_first(), enum_range() etc. are not completely deterministic.

Part of the original motivation for implementing enums was precisely so 
that they would sort in the defined order rather than in lexicographical 
order. It's a fundamental part of the type and not an optional feature. 
The idea of potentially breaking it makes no more sense than allowing 
for a non-deterministic ordering of integers.

cheers

andrew