BEGIN;
BEGIN
SET client_min_messages TO NOTICE;
SET
-- q1
SELECT * FROM pgr_maxCardinalityMatch(
    'SELECT id, source, target, cost AS going, reverse_cost AS coming FROM edge_table'
);
 seq | edge | source | target 
-----+------+--------+--------
   1 |    1 |      1 |      2
   2 |    3 |      4 |      3
   3 |    9 |      6 |      9
   4 |    6 |      7 |      8
   5 |   14 |     10 |     13
   6 |   13 |     11 |     12
   7 |   17 |     14 |     15
   8 |   18 |     16 |     17
(8 rows)

-- q2
SELECT * FROM pgr_maxCardinalityMatch(
    'SELECT id, source, target, cost AS going, reverse_cost AS coming FROM edge_table',
    directed := false
);
 seq | edge | source | target 
-----+------+--------+--------
   1 |    1 |      1 |      2
   2 |    3 |      3 |      4
   3 |    9 |      6 |      9
   4 |    6 |      7 |      8
   5 |   14 |     10 |     13
   6 |   13 |     11 |     12
   7 |   17 |     14 |     15
   8 |   18 |     16 |     17
(8 rows)

-- q3
ROLLBACK;
ROLLBACK
