Re: Documentation clarification request: pg_dumpall and Large Objects

Il Gio 4 Dic 2025, 16:50 Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> ha scritto:

> On Thu, 2025-12-04 at 13:12 +0100, Radoulov, Dimitre wrote:
> > I would like to request a clarification in the pg_dumpall
> > documentation regarding Large Objects (LOBs). The current
> > documentation does not explicitly state whether pg_dumpall includes
> > Large Objects in its output.
> >
> > This behavior is clear from the implementation, but not from the
> > documentation.
> >
> > I propose adding an explicit note such as:
> >
> > "pg_dumpall does not include Large Objects (BLOBs). To back up
> > Large Objects, use pg_dump -b per database."
>
> At the beginning of the "pg_dumpall" page we see:
>
> pg_dumpall is a utility for writing out (“dumping”) all PostgreSQL
> databases
> of a cluster into one script file. [...].
> It does this by calling pg_dump for each database in the cluster.
>
> And the pg_dump documentation says:
>
> -b
> --large-objects
> --blobs (deprecated)
>
> Include large objects in the dump. This is the default behavior except
> when
> --schema, --table, --schema-only, --statistics-only, or --no-data is
> specified.
>
> Since pg_dumpall dumps the databases (and not parts of the databases), it
> will
> automatically dump large objects too.
>
> But I admit that you have to go by circumstantial evidence here. But
> rather
> than explicitly naming large objects, perhaps it would be useful to add
> something
> like
>
> pg_dumpall is primarily intended as a tool to upgrade database clusters.
> As such, it by default exports all data of the entire cluster.
> The only part of the state of a database cluster that is *not* included
> in the output of pg_dumpall are the configuration files and database
> parameters
> changed with ALTER SYSTEM.
>

Thank you for the clarification.

I believe the confusion comes from the historical behavior of pg_dump in
older PostgreSQL versions.

Since pg_dumpall delegates to pg_dump, and pg_dump’s default behavior has
included LOBs since 7.1, the current behavior is consistent with your
explanation.

Thank you again for your time and for considering the suggestion.

Best regards
Dimitre

>