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Message-ID: <c1175bb1-53c3-4c6d-9762-665992dcf548@aklaver.com>
Date: Wed, 23 Apr 2025 13:19:02 -0700
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Subject: Re: Dump version issues
To: Pawel Veselov <pawel.veselov@gmail.com>
Cc: pgsql-general@lists.postgresql.org
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From: Adrian Klaver <adrian.klaver@aklaver.com>
In-Reply-To: <CAMnJ+BdUEu2vNxCEzMtOq2tYPGx2ag1Djm-nP41fPUVV35kY9g@mail.gmail.com>
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On 4/23/25 13:02, Pawel Veselov wrote:
> On Wed, Apr 23, 2025 at 9:13 PM Adrian Klaver <adrian.klaver@aklaver.com> wrote:
> 
>> On 4/23/25 11:46, Pawel Veselov wrote:
>>> Hello.
>>
>>> So, how come older software (according to versions) produces dump
>>> files with a greater version
>>> than the newer software can understand? Is this Ubuntu package
>>> maintainers messing things up?
>>
>> Do:
>>
>> man postgresql-common
>>
>> to see how this handled.
>>
>> I have found that it is best to be explicit using the --cluster option.
> 
> Thank you, I would have never guessed.
> 
> $ pg_dump -V -h x
> pg_dump (PostgreSQL) 17.4 (Ubuntu 17.4-1.pgdg22.04+2)
> $ pg_dump -V
> pg_dump (PostgreSQL) 12.20 (Ubuntu 12.20-0ubuntu0.20.04.1)
> 
> (facepalm)
> 
> I was using the latter checking what pg_dump version was actually being used.
> Wasn't aware of this pg_wrapper business.

If you do something like:

ls -al /usr/bin/pg_dump

you will find pg_dump is a sym link to:

/usr/share/postgresql-common/pg_wrapper

which is a Perl script that does the selection.

The same holds for the other Postgres commands in /usr/bin/.

FYI, psql will always resolve to latest version installed, --cluster 
will have no affect on it.

> 
>> Given a pg_dump, it would be nice if its "-V" output would say which
>> version of the dump it would produce
> 
> Yeah, this wouldn't have helped a bit.

-- 
Adrian Klaver
adrian.klaver@aklaver.com