Re: GROUP BY and inheritance issue

David Rowley <david.rowley@2ndquadrant.com>

From: David Rowley <david.rowley@2ndquadrant.com>
To: Manuel Rigger <rigger.manuel@gmail.com>
Cc: PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Date: 2019-07-03T22:11:55Z
Lists: pgsql-bugs
On Wed, 3 Jul 2019 at 01:13, David Rowley <david.rowley@2ndquadrant.com> wrote:
>
> On Wed, 3 Jul 2019 at 00:47, Manuel Rigger <rigger.manuel@gmail.com> wrote:
> > Consider the example below:
> >
> > CREATE TABLE t0(c0 INT PRIMARY KEY, c1 INT);
> > CREATE TABLE t1(c0 INT) INHERITS (t0);
> > INSERT INTO t0(c0, c1) VALUES(0, 0);
> > INSERT INTO t1(c0, c1) VALUES(0, 1);
> > SELECT c0, c1 FROM t0 GROUP BY c0, c1; -- expected: 0|0 and 0|1, actual: 0|0
> >
> > Note that column c0 in t0 and t1 are merged. The GROUP BY clause above
> > causes only one row to be fetched, while I'd expect that both are
> > fetched (which is the behavior when no GROUP BY is used). Section
> > 5.9.1 [1] in the documentation mentions some caveats of using
> > inheritance, also stating that the PRIMARY KEY is not inherited. Is
> > this some implication of this or a bug?
>
> Thanks for the report.  This is a bug.

I've pushed a fix for this.


--
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services



Commits

  1. Don't remove surplus columns from GROUP BY for inheritance parents