| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Craig Ringer <craig(at)2ndquadrant(dot)com> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com>, "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>, Josh berkus <josh(at)agliodbs(dot)com>, Justin Clift <justin(at)postgresql(dot)org>, Merlin Moncure <mmoncure(at)gmail(dot)com>, PostgreSQL Hackers Mailing List <pgsql-hackers(at)postgresql(dot)org>, Simon Riggs <simon(at)2ndquadrant(dot)com> |
| Subject: | Re: Lets (not) break all the things. Was: [pgsql-advocacy] 9.6 -> 10.0 |
| Date: | 2016-06-21 16:15:02 |
| Message-ID: | 20160621161502.GH24184@momjian.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Tue, Jun 21, 2016 at 08:56:09PM +0800, Craig Ringer wrote:
> Also, if you run *with* --link, IIRC there's no guarantee that the old version
> will be happy to see any new infomask bits etc introduced by the new Pg. I
Well, we only write system tables in pg_upgrade in the new cluster, and
those are not hard linked. As far as I know, we never write to anything
we hard link from the old cluster.
> think there will also be issues with oid to relfilenode mappings in pg_class if
> the new cluster did any VACUUM FULLs or anything. It seems likely to be a bit
pg_upgrade turns off all vacuums.
> risky to fall back on the old cluster once you've upgraded with --link . TBH it
> never even occurred to me that it'd be possible at all until you mentioned.
Well, with --link, you can't start the old cluster, and that is
documented, and pg_control is renamed to prevent accidental start. I
think it is possible to start the old cluster before the new cluster is
started.
> I always thought of pg_upgrade as a one-way no-going-back process either way,
> really. Either due to a fork in history (without --link) or due to possibly
> incompatible datadir changes (with --link).
Yes.
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ As you are, so once was I. As I am, so you will be. +
+ Ancient Roman grave inscription +
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Bruce Momjian | 2016-06-21 16:15:34 | Re: Lets (not) break all the things. Was: [pgsql-advocacy] 9.6 -> 10.0 |
| Previous Message | Robert Haas | 2016-06-21 16:12:34 | Re: Lets (not) break all the things. Was: [pgsql-advocacy] 9.6 -> 10.0 |