From: Paul Ramsey <pramsey@cleverelephant.ca>
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Subject: Pg18 Recursive Crash
Message-Id: <99F064C1-B3EB-4BE7-97D2-D2A0AA487A71@cleverelephant.ca>
Date: Mon, 16 Dec 2024 09:50:39 -0800
To: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Archived-At: <https://www.postgresql.org/message-id/99F064C1-B3EB-4BE7-97D2-D2A0AA487A71%40cleverelephant.ca>
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Apologies if this is already reported, but there=E2=80=99s a crasher in =
recursive queries at the head of the current development that happened =
to be exercised by our regression suite. Here is a core-only =
reproduction.

CREATE TABLE foo (id integer, x integer, y integer);
INSERT INTO foo VALUES (1, 0, 1);
INSERT INTO foo VALUES (2, 1, 2);
INSERT INTO foo VALUES (3, 2, 3);

WITH RECURSIVE path (id, x, y) AS (
    SELECT id, x, y FROM foo WHERE id =3D 1
    UNION
    SELECT foo.id, foo.x, foo.y
    FROM path, foo
    WHERE path.y =3D foo.x
)
SELECT 'crash', id, x, y FROM path;


Thanks!
ATB,
P=