Horton

Re: BUG #17646: create rule named "_RETURN" will cause pg core

Ilya Anfimov <ilan@tzirechnoy.com>

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From: Ilya Anfimov <ilan@tzirechnoy.com>
To: pgsql-bugs@lists.postgresql.org
Date: 2022-10-17T14:33:38Z
Lists: pgsql-bugs 
On Mon, Oct 17, 2022 at 10:17:55AM -0400, Tom Lane wrote:
> PG Bug reporting form <noreply@postgresql.org> writes:
> > here is a test case
> 
> > create table t (id integer);
> > create view v1 as select * from t;
> > create or replace rule "_RETURN" as on UPDATE to v1 do instead select * from
> > t;
> 
> Meh.  We should be preventing you from doing that.
> 
> (Although the core dump is also not great --- something should've noticed
> the bogosity of the plan earlier than this.)

 Id doesn't look much of a plan bogosity,
but rather implicit deletion of the "_RETURN" on select rule.

Consider the behaviour of the direct drop rule:

ilan=*> create table t (id integer);
CREATE TABLE
ilan=*> create view v1 as select * from t;
CREATE VIEW
ilan=*> DROP RULE "_RETURN" ON v1;
ERROR:  cannot drop rule _RETURN on view v1 because view v1 requires it
ПОДСКАЗКА:  You can drop view v1 instead.

> 
> 			regards, tom lane
>

Commits

  1. Reject non-ON-SELECT rules that are named "_RETURN".

  2. Guard against table-AM-less relations in planner.