我在Windows和PHP上使用最新的MySQL-Version（5.7.21）。
我有2个线程做类似的事情（简化，我试图将其分解为测试和演示）：
Thread 1:
while(true)
{ START TRANSACTION;
SELECT id FROM t FOR UPDATE;
UPDATE t SET ...=...;
COMMIT;
}
Thread 2:
while(true)
{ START TRANSACTION;
SELECT id FROM t WHERE id IN (...) FOR UPDATE;
UPDATE t SET ...=... WHERE id IN (...);
COMMIT;
}
我的问题：经过大约10-20轮后，我得到了：
Deadlock found when trying to get lock; try restarting transaction
in SELECT id FROM t WHERE id IN(...)
我不确定为什么这是一个僵局。有什么想法吗？
奇怪的是，在每次COMMIT之后进行睡眠（1）时它都有效。
添加了：
show engine innodb status;
------------------------
LATEST DETECTED DEADLOCK
------------------------
2018-04-08 16:50:30 0x15d0
*** (1) TRANSACTION:
TRANSACTION 162475673, ACTIVE 0 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 1136, 1 row lock(s)
MySQL thread id 121, OS thread handle 1592, query id 91399 localhost 127.0.0.1 root statistics
SELECT id FROM t WHERE t.id IN('1') FOR UPDATE
*** (1) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 40153 page no 17 n bits 104 index PRIMARY of table `db`.`t` trx id 162475673 lock_mode X locks rec but not gap waiting
Record lock, heap no 2 PHYSICAL RECORD: n_fields 49; compact format; info bits 0
0: len 4; hex 00000001; asc ;;
1: len 6; hex 000009af2e7d; asc .};;
2: len 7; hex 5600010b002a9a; asc V * ;;
3: len 30; hex 4d4848484848484848484848484848484848484848484848484848484848; asc MHHHHHHHHHHHHHHHHHHHHHHHHHHHHH; (total 255 bytes);
4: len 0; hex ; asc ;;
5: SQL NULL;
6: SQL NULL;
7: len 0; hex ; asc ;;
8: len 0; hex ; asc ;;
9: len 0; hex ; asc ;;
10: len 0; hex ; asc ;;
11: len 0; hex ; asc ;;
12: len 0; hex ; asc ;;
13: SQL NULL;
14: SQL NULL;
15: SQL NULL;
16: SQL NULL;
17: SQL NULL;
18: SQL NULL;
19: SQL NULL;
20: len 1; hex 81; asc ;;
21: len 3; hex 800100; asc ;;
22: len 2; hex 8000; asc ;;
23: len 0; hex ; asc ;;
24: len 1; hex 30; asc 0;;
25: len 0; hex ; asc ;;
26: len 1; hex 81; asc ;;
27: SQL NULL;
28: len 1; hex 80; asc ;;
29: len 0; hex ; asc ;;
30: len 1; hex 01; asc ;;
31: len 4; hex 80000000; asc ;;
32: len 4; hex 80000000; asc ;;
33: len 4; hex 80000000; asc ;;
34: len 4; hex 80000000; asc ;;
35: len 4; hex 80000000; asc ;;
36: SQL NULL;
37: SQL NULL;
38: len 1; hex 80; asc ;;
39: len 1; hex 80; asc ;;
40: len 1; hex 80; asc ;;
41: SQL NULL;
42: len 0; hex ; asc ;;
43: len 4; hex 80000000; asc ;;
44: len 4; hex 00000001; asc ;;
45: len 0; hex ; asc ;;
46: len 4; hex 00000001; asc ;;
47: len 0; hex ; asc ;;
48: len 0; hex ; asc ;;
*** (2) TRANSACTION:
TRANSACTION 162475666, ACTIVE 0 sec starting index read, thread declared inside InnoDB 5000
mysql tables in use 1, locked 1
1823 lock struct(s), heap size 172240, 33299 row lock(s)
MySQL thread id 120, OS thread handle 5584, query id 91402 localhost 127.0.0.1 root updating
UPDATE t SET number=CONCAT(number, 'H')
*** (2) HOLDS THE LOCK(S):
RECORD LOCKS space id 40153 page no 17 n bits 104 index PRIMARY of table `db`.`t` trx id 162475666 lock_mode X locks rec but not gap
Record lock, heap no 2 PHYSICAL RECORD: n_fields 49; compact format; info bits 0
0: len 4; hex 00000001; asc ;;
1: len 6; hex 000009af2e7d; asc .};;
2: len 7; hex 5600010b002a9a; asc V * ;;
3: len 30; hex 4d4848484848484848484848484848484848484848484848484848484848; asc MHHHHHHHHHHHHHHHHHHHHHHHHHHHHH; (total 255 bytes);
4: len 0; hex ; asc ;;
5: SQL NULL;
6: SQL NULL;
7: len 0; hex ; asc ;;
8: len 0; hex ; asc ;;
9: len 0; hex ; asc ;;
10: len 0; hex ; asc ;;
11: len 0; hex ; asc ;;
12: len 0; hex ; asc ;;
13: SQL NULL;
14: SQL NULL;
15: SQL NULL;
16: SQL NULL;
17: SQL NULL;
18: SQL NULL;
19: SQL NULL;
20: len 1; hex 81; asc ;;
21: len 3; hex 800100; asc ;;
22: len 2; hex 8000; asc ;;
23: len 0; hex ; asc ;;
24: len 1; hex 30; asc 0;;
25: len 0; hex ; asc ;;
26: len 1; hex 81; asc ;;
27: SQL NULL;
28: len 1; hex 80; asc ;;
29: len 0; hex ; asc ;;
30: len 1; hex 01; asc ;;
31: len 4; hex 80000000; asc ;;
32: len 4; hex 80000000; asc ;;
33: len 4; hex 80000000; asc ;;
34: len 4; hex 80000000; asc ;;
35: len 4; hex 80000000; asc ;;
36: SQL NULL;
37: SQL NULL;
38: len 1; hex 80; asc ;;
39: len 1; hex 80; asc ;;
40: len 1; hex 80; asc ;;
41: SQL NULL;
42: len 0; hex ; asc ;;
43: len 4; hex 80000000; asc ;;
44: len 4; hex 00000001; asc ;;
45: len 0; hex ; asc ;;
46: len 4; hex 00000001; asc ;;
47: len 0; hex ; asc ;;
48: len 0; hex ; asc ;;
*** (2) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 40153 page no 17 n bits 104 index PRIMARY of table `db`.`t` trx id 162475666 lock_mode X waiting
Record lock, heap no 2 PHYSICAL RECORD: n_fields 49; compact format; info bits 0
0: len 4; hex 00000001; asc ;;
1: len 6; hex 000009af2e7d; asc .};;
2: len 7; hex 5600010b002a9a; asc V * ;;
3: len 30; hex 4d4848484848484848484848484848484848484848484848484848484848; asc MHHHHHHHHHHHHHHHHHHHHHHHHHHHHH; (total 255 bytes);
4: len 0; hex ; asc ;;
5: SQL NULL;
6: SQL NULL;
7: len 0; hex ; asc ;;
8: len 0; hex ; asc ;;
9: len 0; hex ; asc ;;
10: len 0; hex ; asc ;;
11: len 0; hex ; asc ;;
12: len 0; hex ; asc ;;
13: SQL NULL;
14: SQL NULL;
15: SQL NULL;
16: SQL NULL;
17: SQL NULL;
18: SQL NULL;
19: SQL NULL;
20: len 1; hex 81; asc ;;
21: len 3; hex 800100; asc ;;
22: len 2; hex 8000; asc ;;
23: len 0; hex ; asc ;;
24: len 1; hex 30; asc 0;;
25: len 0; hex ; asc ;;
26: len 1; hex 81; asc ;;
27: SQL NULL;
28: len 1; hex 80; asc ;;
29: len 0; hex ; asc ;;
30: len 1; hex 01; asc ;;
31: len 4; hex 80000000; asc ;;
32: len 4; hex 80000000; asc ;;
33: len 4; hex 80000000; asc ;;
34: len 4; hex 80000000; asc ;;
35: len 4; hex 80000000; asc ;;
36: SQL NULL;
37: SQL NULL;
38: len 1; hex 80; asc ;;
39: len 1; hex 80; asc ;;
40: len 1; hex 80; asc ;;
41: SQL NULL;
42: len 0; hex ; asc ;;
43: len 4; hex 80000000; asc ;;
44: len 4; hex 00000001; asc ;;
45: len 0; hex ; asc ;;
46: len 4; hex 00000001; asc ;;
47: len 0; hex ; asc ;;
48: len 0; hex ; asc ;;
*** WE ROLL BACK TRANSACTION (1)
------------
TRANSACTIONS
------------
Trx id counter 162475684
Purge done for trx's n:o < 162475683 undo n:o < 0 state: running but idle
History list length 28
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 281475162769200, not started
0 lock struct(s), heap size 1136, 0 row lock(s)