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From: Thomas Kellerer <shammat@gmx.net>
To: pgsql-admin@lists.postgresql.org
Subject: Re: Determine potential change in table size after a column dropped?
Date: Mon, 24 Jan 2022 09:44:12 +0100
Message-ID: <171c51df-da5e-d788-e051-8d5c53cf754b@gmx.net> (raw)
In-Reply-To: <84b61f419a0a5ba1049c7d74a85b6790bfe9e1e9.camel@cybertec.at>
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	<84b61f419a0a5ba1049c7d74a85b6790bfe9e1e9.camel@cybertec.at>

Laurenz Albe schrieb am 24.01.2022 um 09:28:
> On Sat, 2022-01-22 at 09:08 -0800, Wells Oliver wrote:
>> I need only drop the column and VACUUM FULL the table, and not the entire DB, right?
>
> Not that VACUUM (FULL) will *not* physically get rid of a dropped column,
> as it just copies the complete rows to a new table.

I always wondered why that is the case.

If the table is rewritten entirely, wouldn't that also be an option to
really get rid of dropped columns?

Is there a technical reason, or just a case of "no one cared enough to change it"?

Regards
Thomas






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