mysql死锁日志解读

-- 事务1
START TRANSACTION;
UPDATE table1 SET amount = amount - 100 WHERE id = 1;
UPDATE table2 SET amount = amount + 100 WHERE id = 2;

-- 事务2
START TRANSACTION;
UPDATE table2 SET amount = amount - 100 WHERE id = 2;
UPDATE table1 SET amount = amount + 100 WHERE id = 1;

LATEST DETECTED DEADLOCK
========================
2023-04-01 12:34:56 0x7f9b8c0b4700
*** (1) TRANSACTION:
TRANSACTION 123456, ACTIVE 0 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 3 lock struct(s), heap size 1136, 2 row lock(s)
MySQL thread id 1234, OS thread handle 0x7f9b8c0b4700, query id 123456 localhost user updating
UPDATE table1 SET amount = amount - 100 WHERE id = 1
*** (1) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 123 page no 4 n bits 72 index `PRIMARY` of table `test`.`table2` trx id 123456 lock_mode X waiting
Record lock, heap no 1 PHYSICAL RECORD: n_fields 3; compact format; info bits 0
 0: len 4; hex 80000002; asc     ;;
 1: len 6; hex 000000000002; asc     ;;
 2: len 7; hex 0000000000000064; asc     d;;

*** (2) TRANSACTION:
TRANSACTION 123457, ACTIVE 0 sec starting index read
mysql tables in use 1, locked 1
3 lock struct(s), heap size 1136, 2 row lock(s)
MySQL thread id 1235, OS thread handle 0x7f9b8c0b4701, query id 123457 localhost user updating
UPDATE table2 SET amount = amount - 100 WHERE id = 2
*** (2) HOLDS THE LOCK(S):
RECORD LOCKS space id 123 page no 3 n bits 72 index `PRIMARY` of table `test`.`table1` trx id 123457 lock_mode X locks rec but not gap
Record lock, heap no 1 PHYSICAL RECORD: n_fields 3; compact format; info bits 0
 0: len 4; hex 80000001; asc     ;;
 1: len 6; hex 000000000001; asc     ;;
 2: len 7; hex 0000000000000064; asc     d;;

*** (2) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 123 page no 4 n bits 72 index `PRIMARY` of table `test`.`table2` trx id 123457 lock_mode X waiting
Record lock, heap no 1 PHYSICAL RECORD: n_fields 3; compact format; info bits 0
 0: len 4; hex 80000002; asc     ;;
 1: len 6; hex 000000000002; asc     ;;
 2: len 7; hex 0000000000000064; asc     d;;

*** WE ROLL BACK TRANSACTION (2)

-- 事务1
START TRANSACTION;
UPDATE table1 SET amount = amount - 100 WHERE id = 1;
UPDATE table2 SET amount = amount + 100 WHERE id = 2;
COMMIT;

-- 事务2
START TRANSACTION;
UPDATE table1 SET amount = amount + 100 WHERE id = 1;
UPDATE table2 SET amount = amount - 100 WHERE id = 2;
COMMIT;