Re: Non-text mode for pg_dumpall

From: Mahendra Singh Thalor <mahi6run(at)gmail(dot)com>
To: Álvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
Cc: Noah Misch <noah(at)leadboat(dot)com>, Andrew Dunstan <andrew(at)dunslane(dot)net>, jian he <jian(dot)universality(at)gmail(dot)com>, Srinath Reddy <srinath2133(at)gmail(dot)com>, pgsql-hackers(at)lists(dot)postgresql(dot)org
Subject: Re: Non-text mode for pg_dumpall
Date: 2025-07-17 12:52:38
Message-ID: CAKYtNAq1N_2b0hS9w0+HSoQZC7o+axzBuYg2O4806N9e06mpqw@mail.gmail.com
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Thanks Álvaro for the feedback.

On Thu, 17 Jul 2025 at 16:41, Álvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
wrote:
>
> On 2025-Jul-17, Mahendra Singh Thalor wrote:
>
> > To pg_restore, we are giving a dump of pg_dumpall which has a
> > global.dat file and we have drop commands in the global.dat file so
> > when we are using 'globals-only', we are dropping databases as we have
> > DROP commands.
> > As of now, we don't have any filter for global.dat file in restore. If
> > a user wants to restore only globals(without droping db), then they
> > should use 'globals-only' in pg_dumpall.
> > Or if we don't want to DROP databases by global.dat file, then we
> > should add a filter in pg_restore (hard to implement as we have SQL
> > commands in global.dat file).
>
> I think dropping database is dangerous and makes no practical sense;
> doing it renders pg_dumpall --clean completely unusable. You're arguing
> from the point of view of ease of implementation, but that doesn't help
> users.

I have 2 more solutions for this case.
*Solution1*: dump DROP database/role/tablespace commands in global_drop.dat
(or dump only DROP DATABASE commands in global_drop.dat file) and skip
restoring this file with globals-only.
*Solution2*: add one more filter in restore to skip the "DROP DATABASE"
command as we already have one filter for "CREATE USER".

Based on *solution1*, I made a WIP patch. Here, I am attaching a patch for
feedback.

Note: please use this v02 patch for review.

>
> > I think, for this case, we can do some
> > more doc changes.
> > Example: pg_restore --globals-only : this will restore the global.dat
> > file(including all drop commands). It might drop databases if any drop
> > commands.
>
> I don't think doc changes are useful.
>
> --
> Álvaro Herrera 48°01'N 7°57'E —
https://www.EnterpriseDB.com/
> "I love the Postgres community. It's all about doing things _properly_.
:-)"
> (David Garamond)

--
Thanks and Regards
Mahendra Singh Thalor
EnterpriseDB: http://www.enterprisedb.com

Attachment Content-Type Size
v02-17-july-use-appendShellString-to-append-file-names.noci application/octet-stream 15.2 KB

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