Re: Removing pg_migrator limitations

Bruce Momjian <bruce@momjian.us>

From: Bruce Momjian <bruce@momjian.us>
To: Andrew Dunstan <andrew@dunslane.net>
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: 2009-12-24T01:33:38Z
Lists: pgsql-hackers
Andrew Dunstan wrote:
> 
> 
> 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.

I had no idea we exposed that API.

> 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.

OK, I get the point.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +