Re: upgrade and migrate

Thank you everybody for your suggestions.
So, to summarize - we can run pg_upgrade from 8.3 to 9.4 (in place), fix app related issues (if any), then migrate to a version more recent than 9.6, either through pg_basebackup or through logical replication (if we would upgrade to version 10).

First step requires downtime. Second does not. Correct?

-Julie

________________________________
From: Tom Lane <[email protected]>
Sent: Wednesday, December 4, 2019 5:28 AM
To: Stephen Frost <[email protected]>
Cc: Laurenz Albe <[email protected]>; Michael Paquier <[email protected]>; Julie Nishimura <[email protected]>; [email protected] <[email protected]>; pgsql-general <[email protected]>
Subject: Re: upgrade and migrate

Stephen Frost <[email protected]> writes:
> * Laurenz Albe ([email protected]) wrote:
>> Right, Slony is the way to go, since pg_upgrade doesn't support 8.3.
>> I would upgrade to a version more recent than 9.6.

> So...  there's a bit of history here.  pg_upgrade in 9.4 actually does
> support upgrading from 8.3.X.  Support for upgrading from 8.3 was
> removed in 2209b3923a7afe0b6033ecfea972219df252ca8e.

Yeah.  Also note that 8.3 to 9.6-or-newer is going to be a pretty
huge jump in terms of minor compatibility issues (have you read
all the relevant release notes?).  So there's something to be said
for breaking this down into two steps: update to 9.4, test/fix
your applications against that, then make a second jump to something
current.  Each of those jumps could be handled by the respective
version of pg_upgrade.  I concur with Laurenz's advice that stopping
at 9.6 is probably not your best choice for a migration today.

                        regards, tom lane