From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alexander Lakhin <exclusion@gmail.com>
cc: pgsql-bugs@lists.postgresql.org,
        Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Subject: Re: BUG #17872: Dropping an attribute of a composite type breaks
 indexes over the type silently
In-reply-to: <67cb509e-93c7-1c7b-2388-d7e00277b344@gmail.com>
References: <17872-d0fbb799dc3fd85d@postgresql.org>
 <3169550.1679928579@sss.pgh.pa.us> <3182314.1679935605@sss.pgh.pa.us>
 <1aa2eec0-2017-3870-6d88-228d08c587d3@gmail.com>
 <3267914.1679941213@sss.pgh.pa.us>
 <67cb509e-93c7-1c7b-2388-d7e00277b344@gmail.com>
Comments: In-reply-to Alexander Lakhin <exclusion@gmail.com>
	message dated "Mon, 27 Mar 2023 22:00:00 +0300"
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Date: Mon, 27 Mar 2023 15:06:21 -0400
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Alexander Lakhin <exclusion@gmail.com> writes:
> 27.03.2023 21:20, Tom Lane wrote:
>> Hmm ... really?  I'd just concluded that a partitioned table is okay
>> as long as it doesn't yet have any partitions.  Even if the modified
>> type is a partitioning column, there's no structure yet that could
>> depend on the contents of the type.  (If it does have partitions,
>> we'll fail when we get to one of those.)

> The following query leads to a failure on showing a partition definition:
> CREATE TABLE tbl(a int, b int) PARTITION BY LIST ((tbl));
> CREATE TABLE tblp PARTITION OF tbl FOR VALUES IN ('(2,4)');
> ALTER TABLE tbl ALTER COLUMN a TYPE char(5);

Sure, but there you already have a partition.  If you only had "tbl"
then there would be no stored partition bounds.

			regards, tom lane