Questa è quasi sicuramente la causa dell'altra mia domanda , ma ho pensato che valesse la pena separarli perché ho un'ipotesi basata sul seguente registro che mi piacerebbe avere falsificato o verificato.
La mia ipotesi è che l' altro deadlock sia in realtà il risultato delle seguenti query, con la query originale nascosta in base alla mia comprensione, lo stato innodb mostra solo le transazioni più recenti (è corretto?).
Sulla base del registro, ho controllato il nostro codice e ho trovato le seguenti due query eseguite in sequenza:
db.Execute("UPDATE people SET iphone_device_id=NULL WHERE iphone_device_id=@0 AND people_id<>@1", DeviceID, m_User.people_id);
// I have hard coded this query in this snippet to simplify things
db.Execute("UPDATE people SET company_id = 444, name = 'Dad', password = '<pass>', temp_password = NULL, reset_password_hash = NULL, email = '<redacted>@gmail.com', phone = NULL, mobile = NULL, iphone_device_id = 'iphone:<device_id_blah>', iphone_device_time = '2011-06-06 19:12:29', last_checkin = '2011-06-07 02:49:47', location_lat = <lat>, location_long = <lng>, gps_strength = 66, picture_blob_id = 1661, authority = 1, active = 1, date_created = '2011-03-20 19:18:34', last_login = '2011-06-07 11:15:01', panic_mode = 0, battery_level = 0.55, battery_state = 'unplugged' WHERE people_id = 666");
Dove db.Execute sta fondamentalmente facendo un ExecuteNonQuery su un oggetto DbCommand System.Data .
Quindi questa sequenza di query si tradurrà in un deadlock? La mia ipotesi è che i due diversi ordini di campo nelle due query causino il problema? Posso concludere le due query in una transazione per risolvere il deadlock?
------------------------
LATEST DETECTED DEADLOCK
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110607 11:15:01
*** (1) TRANSACTION:
TRANSACTION 0 45674214, ACTIVE 0 sec, OS thread id 2584 starting index read
mysql tables in use 1, locked 1
LOCK WAIT 3 lock struct(s), heap size 1216, 2 row lock(s)
MySQL thread id 109, query id 4044915 localhost 127.0.0.1 famdev Searching rows for update
UPDATE people SET iphone_device_id=NULL WHERE iphone_device_id='iphone:<device_id_blah>' AND people_id<>666
*** (1) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 0 page no 4611 n bits 152 index `PRIMARY` of table `family`.`people` trx id 0 45674214 lock_mode X locks rec but not gap waiting
Record lock, heap no 7 PHYSICAL RECORD: n_fields 25; compact format; info bits 0
0: len 8; hex 8000000000000941; asc A;; 1: len 6; hex 000002b8eedf; asc ;; 2: len 7; hex 00000002801064; asc d;; 3: len 8; hex 80000000000004c6; asc ;; 4: len 3; hex 446164; asc Dad;; 5: len 30; hex <data0>; asc <data1>;...(truncated); 6: SQL NULL; 7: SQL NULL; 8: len 17; hex <data2>; asc <redacted>@gmail.com;; 9: SQL NULL; 10: SQL NULL; 11: len 30; hex <data3>; asc iphone:<data4>;...(truncated); 12: len 8; hex <data5>; asc J] };; 13: len 8; hex <data6>; asc J] ;; 14: len 8; hex <data7>; asc ~t g C@;; 15: len 8; hex <data8>; asc G I &S ;; 16: len 2; hex 8042; asc B;; 17: len 8; hex <data9>; asc };; 18: len 4; hex <data10>; asc ;; 19: len 1; hex 81; asc ;; 20: len 8; hex <data11>; asc JL} Z;; 21: len 8; hex <data12>; asc J] M;; 22: len 1; hex 80; asc ;; 23: len 8; hex <data13>; asc ?;; 24: len 9; hex <data14>; asc unplugged;;
*** (2) TRANSACTION:
TRANSACTION 0 45674209, ACTIVE 0 sec, OS thread id 3804 starting index read, thread declared inside InnoDB 500
mysql tables in use 1, locked 1
5 lock struct(s), heap size 1216, 2 row lock(s), undo log entries 1
MySQL thread id 110, query id 4044916 localhost 127.0.0.1 famdev Updating
UPDATE people SET company_id = 444, name = 'Dad', password = '<pass>', temp_password = NULL, reset_password_hash = NULL, email = '<redacted>@gmail.com', phone = NULL, mobile = NULL, iphone_device_id = 'iphone:<device_id_blah>', iphone_device_time = '2011-06-06 19:12:29', last_checkin = '2011-06-07 02:49:47', location_lat = <lat>, location_long = <lng>, gps_strength = 66, picture_blob_id = 1661, authority = 1, active = 1, date_created = '2011-03-20 19:18:34', last_login = '2011-06-07 11:15:01', panic_mode = 0, battery_level = 0.55, battery_state = 'unplugged' WHERE people_id = 666
*** (2) HOLDS THE LOCK(S):
RECORD LOCKS space id 0 page no 4611 n bits 152 index `PRIMARY` of table `family`.`people` trx id 0 45674209 lock mode S locks rec but not gap
Record lock, heap no 7 PHYSICAL RECORD: n_fields 25; compact format; info bits 0
0: len 8; hex 8000000000000941; asc A;; 1: len 6; hex 000002b8eedf; asc ;; 2: len 7; hex 00000002801064; asc d;; 3: len 8; hex 80000000000004c6; asc ;; 4: len 3; hex 446164; asc Dad;; 5: len 30; hex <data0>; asc <data1>;...(truncated); 6: SQL NULL; 7: SQL NULL; 8: len 17; hex <data2>; asc <redacted>@gmail.com;; 9: SQL NULL; 10: SQL NULL; 11: len 30; hex <data3>; asc iphone:<data4>;...(truncated); 12: len 8; hex <data5>; asc J] };; 13: len 8; hex <data6>; asc J] ;; 14: len 8; hex <data7>; asc ~t g C@;; 15: len 8; hex <data8>; asc G I &S ;; 16: len 2; hex 8042; asc B;; 17: len 8; hex <data9>; asc };; 18: len 4; hex <data10>; asc ;; 19: len 1; hex 81; asc ;; 20: len 8; hex <data11>; asc JL} Z;; 21: len 8; hex <data12>; asc J] M;; 22: len 1; hex 80; asc ;; 23: len 8; hex <data13>; asc ?;; 24: len 9; hex <data14>; asc unplugged;;
*** (2) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 0 page no 4611 n bits 152 index `PRIMARY` of table `family`.`people` trx id 0 45674209 lock_mode X locks rec but not gap waiting
Record lock, heap no 7 PHYSICAL RECORD: n_fields 25; compact format; info bits 0
0: len 8; hex 8000000000000941; asc A;; 1: len 6; hex 000002b8eedf; asc ;; 2: len 7; hex 00000002801064; asc d;; 3: len 8; hex 80000000000004c6; asc ;; 4: len 3; hex 446164; asc Dad;; 5: len 30; hex <data0>; asc <data1>;...(truncated); 6: SQL NULL; 7: SQL NULL; 8: len 17; hex <data2>; asc <redacted>@gmail.com;; 9: SQL NULL; 10: SQL NULL; 11: len 30; hex <data3>; asc iphone:<data4>;...(truncated); 12: len 8; hex <data5>; asc J] };; 13: len 8; hex <data6>; asc J] ;; 14: len 8; hex <data7>; asc ~t g C@;; 15: len 8; hex <data8>; asc G I &S ;; 16: len 2; hex 8042; asc B;; 17: len 8; hex <data9>; asc };; 18: len 4; hex <data10>; asc ;; 19: len 1; hex 81; asc ;; 20: len 8; hex <data11>; asc JL} Z;; 21: len 8; hex <data12>; asc J] M;; 22: len 1; hex 80; asc ;; 23: len 8; hex <data13>; asc ?;; 24: len 9; hex <data14>; asc unplugged;;