Re: --single-transaction hack to pg_upgrade does not work - Mailing list pgsql-hackers

Andres Freund <andres@2ndquadrant.com> writes:
> On 2012-12-01 12:00:46 -0500, Tom Lane wrote:
>> ISTM this sort of thing ought to be safe enough, though you probably
>> need to insist both that the pg_type row's xmin be current XID and
>> that it not be HEAP_UPDATED.

> I was concerned about updated rows but forgot about HEAP_UPDATED. So I
> thought that it would be possible to alter the type in some generic
> fashion (e.g. change owner) and then add new values.

Yeah, I was just thinking about that: we'd have to fail if pg_dump
emitted CREATE TYPE, ALTER TYPE OWNER, and then tried to add more
values.  Fortunately it doesn't do that; the ADD VALUE business is
just a multi-statement expansion of CREATE TYPE AS ENUM, and any
other ALTERs will come afterwards.

> Let me provide something a littlebit more mature.

It could do with some comments ;-)
        regards, tom lane