# This is a straightforward deadlock scenario. Since it involves more than # two processes, the main lock detector will find the problem and rollback # the session that first discovers it. Set deadlock_timeout in each session # so that it's predictable which session fails. setup { CREATE TABLE a1 (); CREATE TABLE a2 (); CREATE TABLE a3 (); CREATE TABLE a4 (); CREATE TABLE a5 (); CREATE TABLE a6 (); CREATE TABLE a7 (); CREATE TABLE a8 (); } teardown { DROP TABLE a1, a2, a3, a4, a5, a6, a7, a8; } session s1 setup { BEGIN; SET deadlock_timeout = '100s'; } step s1a1 { LOCK TABLE a1; } step s1a2 { LOCK TABLE a2; } step s1c { COMMIT; } session s2 setup { BEGIN; SET deadlock_timeout = '100s'; } step s2a2 { LOCK TABLE a2; } step s2a3 { LOCK TABLE a3; } step s2c { COMMIT; } session s3 setup { BEGIN; SET deadlock_timeout = '100s'; } step s3a3 { LOCK TABLE a3; } step s3a4 { LOCK TABLE a4; } step s3c { COMMIT; } session s4 setup { BEGIN; SET deadlock_timeout = '100s'; } step s4a4 { LOCK TABLE a4; } step s4a5 { LOCK TABLE a5; } step s4c { COMMIT; } session s5 setup { BEGIN; SET deadlock_timeout = '100s'; } step s5a5 { LOCK TABLE a5; } step s5a6 { LOCK TABLE a6; } step s5c { COMMIT; } session s6 setup { BEGIN; SET deadlock_timeout = '100s'; } step s6a6 { LOCK TABLE a6; } step s6a7 { LOCK TABLE a7; } step s6c { COMMIT; } session s7 setup { BEGIN; SET deadlock_timeout = '100s'; } step s7a7 { LOCK TABLE a7; } step s7a8 { LOCK TABLE a8; } step s7c { COMMIT; } session s8 setup { BEGIN; SET deadlock_timeout = '10ms'; } step s8a8 { LOCK TABLE a8; } step s8a1 { LOCK TABLE a1; } step s8c { COMMIT; } # Note: when s8a1 detects the deadlock and fails, s7a8 is released, making # it timing-dependent which query completion is received first by the tester. # To ensure output stability, add a blocking mark to force s8a1's completion # to be reported first. There is a second timing dependency, too: the tester # might or might not observe s8a1 during its short lock wait state. Apply a # dummy blocking mark to s8a1 to ensure it will be reported as "waiting" # regardless of that. permutation s1a1 s2a2 s3a3 s4a4 s5a5 s6a6 s7a7 s8a8 s1a2 s2a3 s3a4 s4a5 s5a6 s6a7 s7a8(s8a1) s8a1(*) s8c s7c s6c s5c s4c s3c s2c s1c