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From: Amit Langote <amitlangote09@gmail.com>
Date: Fri, 17 Apr 2026 12:30:59 +0900
Message-ID: 
 <CA+HiwqGf_eQNK_bqJzL7YZvXKhpCWsbxxa6pwYVAhQLcPS0rAQ@mail.gmail.com>
Subject: Re: Reject invalid databases in pg_get_database_ddl()
To: Hu Xunqi <huxunqi.08@gmail.com>
Cc: Euler Taveira <euler@eulerto.com>, Lakshmi N <lakshmin.jhs@gmail.com>,
	"pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>,
 Andrew Dunstan <andrew@dunslane.net>
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Hi,

On Fri, Apr 17, 2026 at 11:49=E2=80=AFAM Hu Xunqi <huxunqi.08@gmail.com> wr=
ote:
> On Fri, Apr 17, 2026 at 10:16=E2=80=AFAM Amit Langote <amitlangote09@gmai=
l.com> wrote:
> +       /*
> +        * Reject invalid databases: datconnlimit =3D -2 would be emitted=
 as
> +        * CONNECTION LIMIT =3D -2, which cannot be executed.
> +        */
>
> This comment looks a bit too centered on datconnlimit=3D-2, but the real =
issue is that an invalid pg_database row should not be deparsed into DDL. S=
o, maybe rephrase like:
>
> /*
> * Reject invalid databases. Deparsing a pg_database row in invalid state
> * can produce SQL that is not executable, such as CONNECTION LIMIT =3D -2=
.
> */

I was trying to be precise about datconnlimit =3D -2 being the thing
that produces invalid SQL. But your version covers that with the "such
as CONNECTION LIMIT =3D -2" example, and it's closer to the original,
which was on the right track, just needed to be more precise. Let's go
with it.

--=20
Thanks, Amit Langote

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