Message-ID: <8bc6ffe1e5abeac0fdde1a83d95409f0463af013.camel@j-davis.com>
Subject: Re: Statistics Import and Export
From: Jeff Davis <pgsql@j-davis.com>
To: Tom Lane <tgl@sss.pgh.pa.us>, Corey Huinker <corey.huinker@gmail.com>
Cc: Magnus Hagander <magnus@hagander.net>, Stephen Frost
 <sfrost@snowman.net>,  Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>,
 Matthias van de Meent <boekewurm+postgres@gmail.com>, Peter Smith
 <smithpb2250@gmail.com>, PostgreSQL Hackers
 <pgsql-hackers@lists.postgresql.org>,  Tomas Vondra
 <tomas.vondra@enterprisedb.com>
Date: Mon, 01 Apr 2024 10:39:10 -0700
In-Reply-To: <790773.1711910899@sss.pgh.pa.us>
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On Sun, 2024-03-31 at 14:48 -0400, Tom Lane wrote:
> What happens when
> somebody adds a new stakind (and hence new pg_stats column)?
> You could try to add an overloaded pg_set_attribute_stats
> version with more parameters, but I'm pretty sure that would
> lead to "ambiguous function call" failures when trying to load
> old dump files containing only the original parameters.

Why would you need to overload in this case? Wouldn't we just define a
new function with more optional named parameters?

> =C2=A0 The
> present design is also fragile in that an unrecognized parameter
> will lead to a parse-time failure and no function call happening,
> which is less robust than I'd like.

I agree on this point; I found this annoying when testing the feature.

> So this leads me to suggest that we'd be best off with a VARIADIC
> ANY signature, where the variadic part consists of alternating
> parameter labels and values:

I didn't consider this and I think it has a lot of advantages. It's
slightly unfortunate that we can't make them explicitly name/value
pairs, but pg_dump can use whitespace or even SQL comments to make it
more readable.

Regards,
	Jeff Davis