Message-ID: <1f1bee97-4a8e-c5a1-3b96-82d389b34480@enterprisedb.com>
Date: Fri, 17 Dec 2021 08:03:33 +0100
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Subject: Re: Column Filtering in Logical Replication
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To: Amit Kapila <amit.kapila16@gmail.com>,
 Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Tomas Vondra <tomas.vondra@enterprisedb.com>,
 Rahila Syed <rahilasyed90@gmail.com>, Peter Smith <smithpb2250@gmail.com>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>
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From: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
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On 17.12.21 05:47, Amit Kapila wrote:
> I think in the above sentence, you mean to say "dropped from the
> publication". So, IIUC, you are proposing that if one drops a column
> that was part of the column list of a relation in a publication, an
> error will be raised. Also, if the user specifies CASCADE in Alter
> Table ... Drop Column, then we drop the relation from publication. Is
> that right? BTW, this is somewhat on the lines of what row_filter
> patch is also doing where if the user drops the column that was part
> of row_filter for a relation in publication, we give an error and if
> the user tries to drop the column with CASCADE then the relation is
> removed from the publication.

That looks correct.  Consider how triggers behave: Dropping a column 
that a trigger uses (either in UPDATE OF or a WHEN condition) errors 
with RESTRICT and drops the trigger with CASCADE.