From: | Daniel Farina <daniel(at)heroku(dot)com> |
---|---|
To: | Jeff Davis <pgsql(at)j-davis(dot)com> |
Cc: | Bruce Momjian <bruce(at)momjian(dot)us>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Using pg_upgrade on log-shipping standby servers |
Date: | 2012-07-17 08:02:09 |
Message-ID: | CAAZKuFaqnHZ--eqG1dQE85OF9sZ+DNjhcRdc=Vw2H-cmkP5Nvw@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On Mon, Jul 16, 2012 at 5:29 PM, Jeff Davis <pgsql(at)j-davis(dot)com> wrote:
> On Tue, 2012-07-10 at 11:50 -0400, Bruce Momjian wrote:
>> I don't think we can assume that because pg_upgrade was run on the
>> master and standby that they are binary identical, can we? Technically
>> the user file are identical, but the system catalogs and WAL might be
>> different, hence my suggestion to run rsync before allowing the standby
>> to rejoin the primary.
>
> Do you have plans to change that in the future?
>
> If we know that the user data files are identical between primary and
> replica, it would be nice if we could provide a robust way to avoid
> copying them.
How about this alternative that may sound crazy, but would lend itself
to some unification in archiving:
Could pg_upgrade emit WAL segment(s) to provide continuity of a
timeline? So something like:
* Take down the writable primary for pg_upgrade
* Some WAL is emitted and possibly archived
* The old version, when reaching the special pg_upgrade WAL, could
exit or report its situation having paused replay (as clearly, it
cannot proceed). Unsure.
* Start up a new version of postgres on the same cluster at that
point, which plays the upgrade-WAL.
I see this being pretty mechanically intensive, but right now my hands
are completely tied as to achieving total continuity of my archives,
costing a base-backup's worth of risk window upon upgrade.
--
fdr
From | Date | Subject | |
---|---|---|---|
Next Message | Kyotaro HORIGUCHI | 2012-07-17 09:01:10 | Re: pl/perl and utf-8 in sql_ascii databases |
Previous Message | Daniel Farina | 2012-07-17 06:45:43 | Re: Synchronous Standalone Master Redoux |