Michael Paquier wrote:
> On Mon, Jul 13, 2015 at 9:03 PM, Sawada Masahiko <sawada.mshk@gmail.com> wrote:
> > We use script file which are generated by pg_upgrade.
>
> I haven't followed this thread closely, but I am sure you recall that
> vacuumdb has a parallel mode.
I think having to vacuum the whole database during pg_upgrade (or
immediately thereafter, which in practice means that the database is
unusable for queries until that has finished) is way too impractical.
Even in parallel mode, it could take far too long. People already
complain that our upgrading procedure takes too long as opposed to that
of other database systems.
I don't think there's any problem with rewriting the existing server's
VM file into "vfm" format during pg_upgrade, since we expect those files
to be much smaller than the data itself.
--
Álvaro Herrera http://www.2ndQuadrant.com/
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