On Wed, Aug 8, 2012 at 06:42:27PM -0400, Tom Lane wrote:
> Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> > Excerpts from Bruce Momjian's message of mié ago 08 17:15:38 -0400 2012:
> >> On Wed, Aug 8, 2012 at 04:23:04PM -0400, Robert Haas wrote:
> >>> I think this is one good idea:
> >>> http://archives.postgresql.org/message-id/29806.1340655654@sss.pgh.pa.us
>
> >> If we currently require 14 steps to use pg_upgrade, how would that
> >> reduce this number? What failures does it fix?
>
> > The suggestion by Tom reduces the list by two steps because it doesn't
> > need to adjust pg_hba.conf or put it back in the original way
> > afterwards.
>
> Even more to the point, it flat-out eliminates failure modes associated
> with somebody connecting to either the old or the new cluster while
> pg_upgrade is working. Schemes that involve temporarily hacking
> pg_hba.conf can't provide any iron-clad guarantee, because if pg_upgrade
> can connect to a postmaster, so can somebody else.
We now use a temporary port number, 50432.
> The point I think Robert was trying to make is that we need to cut down
> not only the complexity of running pg_upgrade, but the number of failure
> modes. At least that's how I'd define improvement here.
Agreed. Even with these changes, I still see a lot of complexity.
-- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB
http://enterprisedb.com
+ It's impossible for everything to be true. +