Parsed test spec with 2 sessions starting permutation: r1 r2 w1 w2 c1 c2 step r1: SELECT * FROM test; i step r2: SELECT * FROM test; i step w1: INSERT INTO test VALUES (42); step w2: INSERT INTO test VALUES (42); step c1: COMMIT; step w2: <... completed> error in steps c1 w2: ERROR: could not serialize access due to read/write dependencies among transactions step c2: COMMIT; starting permutation: r1 w1 c1 r2 w2 c2 step r1: SELECT * FROM test; i step w1: INSERT INTO test VALUES (42); step c1: COMMIT; step r2: SELECT * FROM test; i 42 step w2: INSERT INTO test VALUES (42); ERROR: duplicate key value violates unique constraint "test_pkey" step c2: COMMIT;