Re: Is it time to kill support for very old servers?

On Fri, Oct 7, 2016 at 3:06 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> pg_dump alleges support for dumping from servers back to 7.0. Would v10
> be a good time to remove some of that code? It's getting harder and
> harder to even compile those ancient branches, let alone get people to
> test against them (cf. 4806f26f9). My initial thought is to cut support
> for pre-7.3 or maybe pre-7.4 servers, as that would allow removal of
> support for cases where the server lacks schemas or pg_depend, each of
> which requires a fair deal of klugery in pg_dump.

I might be expected to be the holdout here but it seems sensible to
me. Removing code in pg_dump to deal with lacking schemas and
pg_depend seems like a major simplification.

> In the same line, maybe we should kill libpq's support for V2 protocol
> (which would make the cutoff 7.4). And maybe the server's support too,
> though that wouldn't save very much code. The argument for cutting this
> isn't so much that we would remove lots of code as that we're removing
> code that never gets tested, at least not by us.

If it's testing we're concerned about IIRC the current servers can be
arm-twisted into speaking V2 protocol. So it should be possible to
test both modern servers and modern pg_dump using V2 protocol with a
simple tweak.

Somehow removing the whole protocol support seems a bit different to
me than removing pg_dump logic. For one it's nice to be able to run a
modern psql against old servers so you can run a benchmark script. For
another there may be binary-only applications or drivers out there
that are using V2 for whatever reason.

--
greg