On Thu, Sep 6, 2012 at 3:58 AM, "Stéphane A. Schildknecht"
<stephane.schildknecht at postgresql.fr> wrote:
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> Hello,
>
> I currently have a 1.2 slony cluster replicating PostgreSQL 8.2 databases.
>
> On our way to migrate to PostgreSQL 9.2, we would like to use Slony to ease
> the migration process.
>
> But, I wonder which version of Slony I could use, as the version currently
> used won't compile vs PostgreSQL 9.2rc1. Neither would slony 2.1.2 compile
> with PG 8.2.

We did something of a "sea change" with version 2 of Slony; there were
substantial changes provided in PostgreSQL 8.3 that 2.0 and up depend
on, and there is no intent to attempt to get 2.0 and later versions to
work with earlier versions of Postgres.

I'm not certain offhand what is the latest version of Postgres which
version 1.2 supports; what is likely disappointing to you is that I
don't think it gets as far as 9.2.  I see notes in git history
indicating that it has had changes that might bring it as far as 9.0,
but I'd be inclined to be a bit tentative about 9.0.  No doubt there
have been changes in 9.1 and 9.2 that have not been backported into
the 1.2 branch.

This does not indicate that Slony is useless to the purpose, but you
might need to have two phases.

1.  Upgrade from 8.2 to 8.3 or so using Slony 1.2

Theoretically, you could get an upgrade to 9.0, but I'd be inclined to
go from 8.2 to 8.3; that's got much less risk of running into any
issues of parts of 9.0 that weren't totally supported in the 1.2
branch.

2.  Then upgrade from (say) 8.3 to 9.2 using Slony 2.1

That's not as wonderful an answer as you might have wanted, certainly
more work than you'd have preferred.  But it ought to work all the
same.