Date: Wed, 21 Aug 2024 16:14:02 +0900
From: Yugo Nagata <nagata@sraoss.co.jp>
To: Peter Eisentraut <peter@eisentraut.org>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>, jian he
 <jian.universality@gmail.com>
Subject: Re: Disallow USING clause when altering type of generated column
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On Wed, 21 Aug 2024 08:17:45 +0200
Peter Eisentraut <peter@eisentraut.org> wrote:

> A USING clause when altering the type of a generated column does not 
> make sense.  It would write the output of the USING clause into the 
> converted column, which would violate the generation  expression.
> 
> This patch adds a check to error out if this is specified.

I’m afraid you forgot to attach the patch.
It seems for me that this fix is reasonable though.

Regards,
Yugo Nagata

> 
> There was a test for this, but that test errored out for a different 
> reason, so it was not effective.
> 
> discovered by Jian He at [0]
> 
> [0]: 
> https://www.postgresql.org/message-id/CACJufxEGPYtFe79hbsMeOBOivfNnPRsw7Gjvk67m1x2MQggyiQ@mail.gmail.com
> 
> 


-- 
Yugo Nagata <nagata@sraoss.co.jp>