Re: Documentation clarification request: pg_dumpall and Large Objects

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.

Yours,
Laurenz Albe