"WHERE 1 = 2 OR ..." makes planner choose a very inefficient plan - Mailing list pgsql-performance

SELECT count(k0.id)
FROM k0
WHERE 1 = 2
    OR k0.id IN (
        SELECT k1.k0_id
        FROM k1
        WHERE k1.k1k2_id IN (
                SELECT k2.k1k2_id
                FROM k2
                WHERE k2.t = 2
                    AND (coalesce(k2.z, '')) LIKE '%12%'
                )
        );