Re: ALTER TABLE lock downgrades have broken pg_upgrade

On 2016-05-03 13:47:14 -0400, Tom Lane wrote:
> I've been thinking of proposing that it's time (not now, at this point,
> but for 9.7) to rip out libpq's support for V2 protocol as well as
> pg_dump's support for pre-7.4 backends.

+1

> There might be an argument for moving pg_dump's cutoff further than that,
> but going to 7.3 or later is significant because it would allow removal of
> the kluges for schema-less and dependency-less servers. I suggested 7.4
> because it'd comport with removal of V2 wire protocol support, and because
> 7.4 is also our cutoff for describe support in psql.

I think we can be a lot more aggressive moving the cuttoff for psql than
for pg_dump; but that's more an argument ripping out some old psql code.

> I'm hesitant to move the cutoff really far, because we do still hear from
> people running really old versions, and sooner or later those people will
> want to upgrade. It'd be good if they could use a modern pg_dump for the
> purpose.

I think we should consider making the cutoff point for pg_dump somewhat
predicatable. E.g. saying that we support 5 more versions than the
actually maintained ones. The likelihood of breakages seems to
increase a good bit for older versions.

Andres