Re: docs: warn about post-data-only schema dumps with parallel restore. - Mailing list pgsql-hackers

"David G. Johnston" <david.g.johnston@gmail.com> writes:
> On Sun, Jan 25, 2026 at 10:23 PM vaibhave postgres <
> postgresvaibhave@gmail.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?

            regards, tom lane

diff --git a/doc/src/sgml/ref/pg_restore.sgml b/doc/src/sgml/ref/pg_restore.sgml
index 9d91c365214..5d5dbe9c0d2 100644
--- a/doc/src/sgml/ref/pg_restore.sgml
+++ b/doc/src/sgml/ref/pg_restore.sgml
@@ -1215,6 +1215,21 @@ CREATE DATABASE foo WITH TEMPLATE template0;
      </para>
     </listitem>

+    <listitem>
+     <para>
+      Parallel restore (<option>--jobs</option> greater than 1) requires
+      applying dependency information from the archive file to ensure
+      that an object is not restored before other objects it depends on.
+      This information will be incomplete, leading to unexpected restore
+      failures, if the archive does not include object definitions
+      (the <option>pre-data</option> section).  Therefore, avoid
+      using <application>pg_dump</application> options such
+      as <option>--no-schema</option> or <option>-a/--data-only</option>
+      when creating an archive you wish to restore in parallel.  Instead,
+      provide such options to <application>pg_restore</application>.
+     </para>
+    </listitem>
+
     <listitem>
      <para><application>pg_restore</application> cannot restore large objects
       selectively;  for instance, only those for a specific table.  If