From: Tom Lane <tgl@sss.pgh.pa.us>
To: samfelder17@gmail.com
cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18917: "Foreign key constraint drop fails with 'column is
 not in index' unless pg_constraint is queried
In-reply-to: <18917-fea6ac4ccec4e24a@postgresql.org>
References: <18917-fea6ac4ccec4e24a@postgresql.org>
Comments: In-reply-to PG Bug reporting form <noreply@postgresql.org>
	message dated "Thu, 08 May 2025 01:23:53 -0000"
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Date: Wed, 07 May 2025 21:50:34 -0400
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PG Bug reporting form <noreply@postgresql.org> writes:
> when trying to drop a foreign key constraint with an existing index that
> hasn't been used, you need to make a query against constraint table to get
> it working. see below for psql sequence of events
> ```
> mydb=> begin;
> BEGIN
> mydb=*> CREATE INDEX IF NOT EXISTS "child_table_parent_id_idx" ON
> "child_table"("parent_id");
> CREATE INDEX
> ... etc ...

This test case is incomplete on its face. (How was the table created?
Where did "child_table_parent_id_fkey" come from?)  So it's hard to
tell what's going on, much less fix it.  Could we have a complete
reproducer starting from an empty database?

			regards, tom lane