Re: docs: warn about post-data-only schema dumps with parallel restore.

From: "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: vaibhave postgres <postgresvaibhave(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: docs: warn about post-data-only schema dumps with parallel restore.
Date: 2026-03-30 03:20:20
Message-ID: CAKFQuwYtdN4chM2HzcNsOJMvsVqE2LnKGTvndNeGW8s66g0Acg@mail.gmail.com
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On Sun, Mar 29, 2026 at 11:33 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> "David G. Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> writes:
> > On Sun, Jan 25, 2026 at 10:23 PM vaibhave postgres <
> > postgresvaibhave(at)gmail(dot)com> wrote:
> >> Following up on the discussion in [1] about pg_restore failing to
> restore
> >> post-data items due to circular foreign key deadlocks.
> >> I’m attaching a doc patch that adds a warning about using post-data-only
> >> schema dumps together with parallel restore.
>
> > Not a fan of the patch overall though. I'd want to add something to
> > pg_restore noting that use of --jobs for constraint restoration needs
> > schema information to compute the restoration order.
>
> Yeah, dropping this into the list of options is bad. We put caveats
> like that into the Notes section usually.
>
> I also tend to think that it'd be better to document this under
> pg_restore: when people run into this type of failure, they are going
> to go to the pg_restore docs not the pg_dump docs to understand it.
> I guess there could be a case for repeating the info in both the
> pg_dump and pg_restore pages, but that feels a bit verbose.
>
> So maybe like the attached?
>
>
Works for me.

But how about adding something like the following to the pg_dump notes? We
already have the corresponding link going to pg_dump in the pg_restore
notes.

"If producing a non-plaint-text format output see also the pg_restore
documentation for details on how the restore process uses the different
sections."

David J.

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