Re: ALTER EXTENSION UPGRADE, v3

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Dimitri Fontaine <dimitri@2ndquadrant.fr>, "David E. Wheeler" <david@kineticode.com>, Josh Berkus <josh@agliodbs.com>, pgsql-hackers@postgresql.org
Date: 2011-02-10T21:38:15Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> On Thu, Feb 10, 2011 at 3:52 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Again, it's not really any different from the case where the dependent
>> objects are "loose" rather than members of an extension.

> Well, the difference is that loose objects are just on my system,
> whereas extensions are supposed to work on anybody's system.  I'm not
> clear that it's possible to write an extension that depends on a
> relocatable extension in a sensible way.  If it is, objection
> withdrawn.

I don't deny that there are risks here.  But I think the value of being
able to move an extension when it is safe outweighs the difficulty that
sometimes it isn't safe.  I think we can leave making it safer as a
topic for future investigation.

Dimitri did suggest treating an extension as nonrelocatable if there is
any other extension installed that depends on it.  But that seems like
more of a kluge than a nice solution, primarily because it does nothing
for the loose-object risks.  I'd rather just document that moving an
extension post-installation might break things, and leave it at that for
now.

			regards, tom lane