Re: [ADMIN] upgrade path from PG 8.3 to PG 9.5

Greetings,

* David G. Johnston (david.g.johnston@gmail.com) wrote:
> On Tue, Mar 21, 2017 at 9:40 AM, Stephen Frost <sfrost@snowman.net> wrote:
> > * Thorsten Schöning (tschoening@am-soft.de) wrote:
> > > Guten Tag Keith,
> > > am Donnerstag, 23. Februar 2017 um 18:57 schrieben Sie:
> > >
> > > > You can go directly from 8.3 to 9.5. Just be sure and use the
> > > > pg_dump from 9.5 to generate the dump file from 8.3.
> > >
> > > Is there a specific reason for that? My current approach for upgrades
> > > was dumping the old database using the old pg_dump, uninstalling the
> > > old Postgres, installing the new one and restore from the old dump.
> >
> > Yes.  Using the older pg_dump may result in dumps that can't be restored
> > into the newer version of PG because things like keywords have been
> > added and must now be quoted.  There are possibly other things that have
> > been changed between the old version and the new one which would also
> > require the new pg_dump to be used, but keywords are the big one.

> The proper solution to the keyword/identifier quoting problem is to use
> "--quote-all-identifiers".

Using the version of pg_dump to which you are upgrading is an entirely
supported and 'proper' approach to dealing with that issue.  Using
--quote-all-identifiers, in my opinion anyway, leads to rather ugly
results.

As I also mention, there are other things in newer versions that pg_dump
does its best to address (including things like checking for role names
in older versions starting with "pg_", which is not allowed in 9.6+).
Using the pg_dump from the version of PG to which you are upgrading is
the correct and supported approach to doing upgrades.  Using
--quote-all-identifiers is not.

Thanks!

Stephen