Re: BUG #17067: FailedAssertion at castNodeImpl

On Mon, Jun 21, 2021 at 5:48 PM David Rowley <dgrowleyml@gmail.com> wrote:

> On Mon, 21 Jun 2021 at 20:15, PG Bug reporting form
> <noreply@postgresql.org> wrote:
> > run the following sql command through client and the PostgreSQL database
> > process will crash:
> >
> > CREATE TABLE v0 ( v1 FLOAT NOT NULL PRIMARY KEY ) ;
> > WITH v1 AS ( DELETE FROM v0 WHERE v1 <= - - - 9 RETURNING * ) INSERT
> INTO v0
> > VALUES ( - - - - - - 95 ) ;
> > SELECT v1 FROM ( SELECT * FROM v0 UNION ALL SELECT * FROM v0 GROUP BY
> > DISTINCT ROLLUP ( v1 , v1 ) , ROLLUP ( v1 , USER ) , GROUPING SETS ( ROW
> ( )
> > , ( v1 ) ) , ROLLUP ( v1 < - - 61 AND v1 IN ( -2147483648 , - 94 ) , v1
> ) )
> > v1 ORDER BY ( v1 + - - -1 ) , ( v1 + - - v1 IN ( SELECT v1 FALSE FROM (
> > SELECT FROM v0 GROUP BY v1 ) PRECISION ) ) ;
>
> Thanks for the report.  It looks like a thinko in 1d581ce71.   Code
> was added there which insists the initial list element is a List, but
> it's an IntList.  I think the code should just use linitial instead of
> linitial_node.
>
> I'm quite surprised that we don't have a test that picks this up.
>

 A distinct group by clause would help to reveal this issue as:

    explain select * from t GROUP BY distinct a, rollup(b);

Maybe we can add a test case to cover it.

Thanks
Richard