Re: Regression in PL/PGSQL code using RETURN QUERY with Postgres 14

On Thu, Oct 7, 2021 at 2:54 PM Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
wrote:

> On 10/7/21 11:38 AM, Gavin Roy wrote:
> > Hi All,
> >
> > My team was testing against Postgres 14 to ensure we could cleanly
> > upgrade and we ran across a regression in our PL/PGSQL code related to
> > the updates to RETURN QUERY.
> >
> > Our code which works in previous versions of Postgres uses UPDATE
> > RETURNING and INSERT RETURNING in combination with RETURN QUERY. It
> > appears that in the parallelism updates, RETURN QUERY now only accepts
> > SELECT queries.
>
> I'm pretty sure folks are going to want to see an example of the code
> and the errors thrown in version 14.
>

Sorry, I thought that was pretty clear. As an example, this worked prior to
14 and no longer works:

CREATE TABLE foo (
bar SERIAL PRIMARY KEY,
baz TEXT
);

CREATE FUNCTION update_foo(in_bar INT4, in_baz TEXT) RETURNS SETOF foo AS $$
BEGIN
RETURN QUERY UPDATE foo SET baz = in_baz WHERE bar = in_bar RETURNING
bar, baz;
END;
$$ LANGUAGE PLPGSQL;

postgres=# SELECT * FROM update_foo(1, 'baz?');
ERROR: query is not a SELECT
CONTEXT: query: UPDATE foo SET baz = in_baz WHERE bar = in_bar RETURNING
bar, baz
PL/pgSQL function update_foo(integer,text) line 3 at RETURN QUERY