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: vaibhave postgres <postgresvaibhave(at)gmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: docs: warn about post-data-only schema dumps with parallel restore.
Date: 2026-01-27 16:51:58
Message-ID: CAKFQuwbHpDVQt0=nfC7To=AxAkDs6fmvv-40Qcw6z=VtW23GEQ@mail.gmail.com
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On Sun, Jan 25, 2026 at 10:23 PM vaibhave postgres <
postgresvaibhave(at)gmail(dot)com> wrote:

> Hi hackers,
>
> 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.
>
> Thanks.
>
> [1] Re: pg_restore: fails to restore post-data items due to circular FK
> deadlock - Mailing list pgsql-bugs : Postgres Professional
> <https://postgrespro.com/list/id/3908(dot)1717093769(at)sss(dot)pgh(dot)pa(dot)us>
>

The note element would align with the sibling para element.

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.

There is also just a lot of detail here when something like:

<para>Consider always combining pre-data and post-data in the same command
so that parallel restores have the necessary dependency information to
create constraints in parallel.</para>

Any other content related to this probably belongs in the Notes section.

David J.

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