我正在使用MySQL 5.7.26，有什么方法可以显示表锁定历史记录吗？我知道如何使用以下方法检查当前表锁定：
show OPEN TABLES where In_use > 0;
我想避免SQL查询中的表锁定，因此查看历史记录可能会有所帮助。当前的锁定可能无法获取所有锁定的表（也许锁定表查询现在无法执行）。
答案 0 :(得分：0)
今天，我找到了一种在MySQL 5.7中进行显示的方法：
show engine innodb status
这是结果输出的一部分：
====================================
2020-09-25 10:36:53 0x7ff4b4c5d700 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 12 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 762213 srv_active, 0 srv_shutdown, 139997 srv_idle
srv_master_thread log flush and writes: 902210
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 363879865
OS WAIT ARRAY INFO: signal count 448819672
RW-shared spins 0, rounds 425739262, OS waits 209673117
RW-excl spins 0, rounds 4271714439, OS waits 133598673
RW-sx spins 135926, rounds 2757000, OS waits 52788
Spin rounds per wait: 425739262.00 RW-shared, 4271714439.00 RW-excl, 20.28 RW-sx
------------------------
LATEST DETECTED DEADLOCK
------------------------
2020-09-25 10:10:41 0x7ff4b4ce1700
*** (1) TRANSACTION:
TRANSACTION 841893940, 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 108348, OS thread handle 140688980530944, query id 184994716 172.19.104.233 root Searching rows for update
UPDATE r_room_seat SET status = 1,
id = (SELECT @update_id := id),
user_id = 62659,
robot_flag = 1
WHERE room_play_id = 539 and status = 0 and online = 1
LIMIT 1
*** (1) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 3493 page no 528 n bits 176 index PRIMARY of table `room_db`.`r_room_seat` trx id 841893940 lock_mode X locks rec but not gap waiting
Record lock, heap no 56 PHYSICAL RECORD: n_fields 20; compact format; info bits 0
0: len 8; hex 000000000000d649; asc I;;
1: len 6; hex 0000322d9b9a; asc 2- ;;
2: len 7; hex 3e000040042eda; asc > @ . ;;
3: len 8; hex 800000000000021b; asc ;;
4: len 8; hex 8000000000000097; asc ;;
5: len 8; hex 800000000000f4d5; asc ;;
6: len 8; hex 7fffffffffffffff; asc ;;
7: len 8; hex 8000017452aa2c5e; asc tR ,^;;
8: len 4; hex 80000000; asc ;;
9: len 4; hex 80000000; asc ;;
10: len 8; hex 8000017452aa2c5e; asc tR ,^;;
11: len 8; hex 8000017452aa2c5e; asc tR ,^;;
12: len 4; hex 80000001; asc ;;
13: len 1; hex 81; asc ;;
14: len 8; hex 8000000000000005; asc ;;
15: len 10; hex 48415050595f5241494e; asc HAPPY_RAIN;;
16: len 4; hex 80000001; asc ;;
17: len 8; hex 8000000000000000; asc ;;
18: len 8; hex 8000000000000074; asc t;;
19: len 4; hex 80000001; asc ;;
*** (2) TRANSACTION:
TRANSACTION 841893905, ACTIVE 0 sec fetching rows
mysql tables in use 2, locked 2
746 lock struct(s), heap size 90320, 128960 row lock(s)
MySQL thread id 100540, OS thread handle 140688982152960, query id 184994612 172.19.104.233 root Sending data
UPDATE r_room_seat s
SET s.status = 1,
s.room_play_id = (SELECT @update_id := max(room_play_id)),
s.user_id = (
case when s.seat_num = 1
then 63182
when s.seat_num = 2
then 16472
else -1 end
),
s.robot_flag = (
case when s.seat_num = 1
then 1
when s.seat_num = 2
then 0
else 0 end
)
WHERE s.status = 0
and s.online = 1
and s.room_play_id in (
select room_play_id
from (
select room_play_id as room_play_id
from r_room_seat
where room_id = 166
and status = 0
group by room_play_id
having count(*) = 2
limit 1
) a
)
and s.room_id = 166
LIMIT 2
*** (2) HOLDS THE LOCK(S):
RECORD LOCKS space id 3493 page no 528 n bits 176 index PRIMARY of table `room_db`.`r_room_seat` trx id 841893905 lock_mode X
Record lock, heap no 1 PHYSICAL RECORD: n_fields 1; compact format; info bits 0
0: len 8; hex 73757072656d756d; asc supremum;;
您可以获得死锁信息和分析。