当我尝试使用subselect进行UPDATE时，我会遇到死锁。 我在我的应用程序中发现了这个死锁我正在使用Hibernate从数据库获取数据，在我的日志中，我看到下一个：
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction
当我从查询中删除子选择时它解决了死锁，但在我的情况下，这些子查询是必要的。
Nested update with select deadlock
https://www.percona.com/blog/2017/09/25/avoid-shared-locks-from-subqueries-when-possible/
但是这些解决方案并没有解决我的问题。 我做错了什么？ Maby有人有类似的问题，可以提供帮助。
这是我的UPDATE with subselect：
UPDATE mediaplan m
SET m.startDate = IFNULL((SELECT p.blockStartTime
FROM placement p
WHERE p.mediaplan_id = m.id AND p.deleted = FALSE
ORDER BY p.blockStartTime ASC
LIMIT 0, 1), NULL),
m.endDate = IFNULL((SELECT p.blockStartTime
FROM placement p
WHERE p.mediaplan_id = m.id AND p.deleted = FALSE
ORDER BY p.blockStartTime DESC
LIMIT 0, 1), NULL)
WHERE m.id IN (208396);
死锁日志（SHOW ENGINE INNODB STATUS;）
=====================================
2018-03-28 15:00:52 0x700007086000 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 38 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 124 srv_active, 0 srv_shutdown, 9865 srv_idle
srv_master_thread log flush and writes: 9989
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 3037
OS WAIT ARRAY INFO: signal count 5042
RW-shared spins 0, rounds 7370, OS waits 1740
RW-excl spins 0, rounds 47629, OS waits 217
RW-sx spins 268, rounds 7782, OS waits 245
Spin rounds per wait: 7370.00 RW-shared, 47629.00 RW-excl, 29.04 RW-sx
------------------------
LATEST DETECTED DEADLOCK
------------------------
2018-03-28 15:00:32 0x700006f32000
*** (1) TRANSACTION:
TRANSACTION 1767639, ACTIVE 0 sec starting index read
mysql tables in use 3, locked 3
LOCK WAIT 6 lock struct(s), heap size 1136, 4 row lock(s), undo log entries 2
MySQL thread id 1105, OS thread handle 123145416400896, query id 17464 localhost 127.0.0.1 romexdev updating
UPDATE mediaplan m SET m.startDate = IFNULL( (SELECT p.blockStartTime FROM placement p WHERE p.mediaplan_id = m.id AND p.deleted = FALSE ORDER BY p.blockStartTime ASC LIMIT 0, 1), NULL ), m.endDate = IFNULL( (SELECT p.blockStartTime FROM placement p WHERE p.mediaplan_id = m.id AND p.deleted = FALSE ORDER BY p.blockStartTime DESC LIMIT 0, 1), NULL ) WHERE m.id IN (-1,208396)
*** (1) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 1658 page no 541 n bits 320 index PRIMARY of table `openmarket`.`mediaplan` trx id 1767639 lock_mode X locks rec but not gap waiting
Record lock, heap no 16 PHYSICAL RECORD: n_fields 11; compact format; info bits 0
0: len 4; hex 80032e0c; asc . ;;
1: len 6; hex 0000001af8d3; asc ;;
2: len 7; hex 7e000009480854; asc ~ H T;;
3: len 5; hex 99a006fc80; asc ;;
4: len 5; hex 999f748c00; asc t ;;
5: len 4; hex 8000027e; asc ~;;
6: SQL NULL;
7: len 1; hex 00; asc ;;
8: len 5; hex 999f6cc39f; asc l ;;
9: len 5; hex 999f6cc39f; asc l ;;
10: len 4; hex 800000a7; asc ;;
*** (2) TRANSACTION:
TRANSACTION 1767637, ACTIVE 0 sec fetching rows
mysql tables in use 3, locked 3
37 lock struct(s), heap size 3520, 900 row lock(s), undo log entries 2
MySQL thread id 1107, OS thread handle 123145418907648, query id 17455 localhost 127.0.0.1 romexdev Creating sort index
UPDATE mediaplan m SET m.startDate = IFNULL( (SELECT p.blockStartTime FROM placement p WHERE p.mediaplan_id = m.id AND p.deleted = FALSE ORDER BY p.blockStartTime ASC LIMIT 0, 1), NULL ), m.endDate = IFNULL( (SELECT p.blockStartTime FROM placement p WHERE p.mediaplan_id = m.id AND p.deleted = FALSE ORDER BY p.blockStartTime DESC LIMIT 0, 1), NULL ) WHERE m.id IN (-1,208396)
*** (2) HOLDS THE LOCK(S):
RECORD LOCKS space id 1658 page no 541 n bits 320 index PRIMARY of table `openmarket`.`mediaplan` trx id 1767637 lock_mode X locks rec but not gap
Record lock, heap no 16 PHYSICAL RECORD: n_fields 11; compact format; info bits 0
0: len 4; hex 80032e0c; asc . ;;
1: len 6; hex 0000001af8d3; asc ;;
2: len 7; hex 7e000009480854; asc ~ H T;;
3: len 5; hex 99a006fc80; asc ;;
4: len 5; hex 999f748c00; asc t ;;
5: len 4; hex 8000027e; asc ~;;
6: SQL NULL;
7: len 1; hex 00; asc ;;
8: len 5; hex 999f6cc39f; asc l ;;
9: len 5; hex 999f6cc39f; asc l ;;
10: len 4; hex 800000a7; asc ;;
*** (2) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 1752 page no 435722 n bits 240 index PRIMARY of table `openmarket`.`placement` trx id 1767637 lock mode S locks rec but not gap waiting
Record lock, heap no 144 PHYSICAL RECORD: n_fields 31; compact format; info bits 0
0: len 4; hex 80c66779; asc gy;;
1: len 5; hex 999fa60000; asc ;;
2: len 6; hex 0000001af8d7; asc ;;
3: len 7; hex 210000c0160979; asc ! y;;
4: len 5; hex 999f78c6f6; asc x ;;
5: len 1; hex 00; asc ;;
6: len 1; hex 83; asc ;;
7: SQL NULL;
8: len 4; hex 88cb341e; asc 4 ;;
9: len 4; hex 80032e0c; asc . ;;
10: len 4; hex 80033ce3; asc < ;;
11: len 1; hex 01; asc ;;
12: len 5; hex 999fa62440; asc $@;;
13: SQL NULL;
14: SQL NULL;
15: SQL NULL;
16: SQL NULL;
17: SQL NULL;
18: SQL NULL;
19: len 1; hex 00; asc ;;
20: len 5; hex 999f78c6f6; asc x ;;
21: len 5; hex 999f78f020; asc x ;;
22: len 4; hex 80000001; asc ;;
23: SQL NULL;
24: len 1; hex 01; asc ;;
25: len 1; hex 01; asc ;;
26: len 1; hex 00; asc ;;
27: len 1; hex 00; asc ;;
28: len 4; hex 8002afaf; asc ;;
29: len 4; hex 80000012; asc ;;
30: SQL NULL;
*** WE ROLL BACK TRANSACTION (1)
------------
TRANSACTIONS
------------
Trx id counter 1767643
Purge done for trx's n:o < 1767643 undo n:o < 0 state: running but idle
History list length 31
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 281479519987928, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 281479519987024, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 281479519986120, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 281479519985216, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 281479519984312, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 281479519989736, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 281479519988832, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 281479519983408, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
--------
FILE I/O
--------
I/O thread 0 state: waiting for i/o request (insert buffer thread)
I/O thread 1 state: waiting for i/o request (log thread)
I/O thread 2 state: waiting for i/o request (read thread)
I/O thread 3 state: waiting for i/o request (read thread)
I/O thread 4 state: waiting for i/o request (read thread)
I/O thread 5 state: waiting for i/o request (read thread)
I/O thread 6 state: waiting for i/o request (write thread)
I/O thread 7 state: waiting for i/o request (write thread)
I/O thread 8 state: waiting for i/o request (write thread)
I/O thread 9 state: waiting for i/o request (write thread)
Pending normal aio reads: [0, 0, 0, 0] , aio writes: [0, 0, 0, 0] ,
ibuf aio reads:, log i/o's:, sync i/o's:
Pending flushes (fsync) log: 0; buffer pool: 0
508449 OS file reads, 49980 OS file writes, 15796 OS fsyncs
0.24 reads/s, 16384 avg bytes/read, 2.58 writes/s, 0.76 fsyncs/s
-------------------------------------
INSERT BUFFER AND ADAPTIVE HASH INDEX
-------------------------------------
Ibuf: size 1, free list len 3092, seg size 3094, 84 merges
merged operations:
insert 134, delete mark 3, delete 1
discarded operations:
insert 0, delete mark 0, delete 0
Hash table size 34673, node heap has 4 buffer(s)
Hash table size 34673, node heap has 24 buffer(s)
Hash table size 34673, node heap has 62 buffer(s)
Hash table size 34673, node heap has 201 buffer(s)
Hash table size 34673, node heap has 73 buffer(s)
Hash table size 34673, node heap has 2 buffer(s)
Hash table size 34673, node heap has 1 buffer(s)
Hash table size 34673, node heap has 2 buffer(s)
133.47 hash searches/s, 26.13 non-hash searches/s
---
LOG
---
Log sequence number 212087243581
Log flushed up to 212087243581
Pages flushed up to 212087243581
Last checkpoint at 212087243572
0 pending log flushes, 0 pending chkp writes
678 log i/o's done, 0.39 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total large memory allocated 137428992
Dictionary memory allocated 5812878
Buffer pool size 8191
Free buffers 1024
Database pages 6798
Old database pages 2489
Modified db pages 0
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 24521, not young 13076464
0.00 youngs/s, 1.39 non-youngs/s
Pages read 504777, created 29725, written 31405
0.24 reads/s, 0.00 creates/s, 2.11 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 3 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 6798, unzip_LRU len: 0
I/O sum[130]:cur[0], unzip sum[0]:cur[0]
--------------
ROW OPERATIONS
--------------
0 queries inside InnoDB, 0 queries in queue
0 read views open inside InnoDB
Process ID=36398, Main thread ID=123145409064960, state: sleeping
Number of rows inserted 49479, updated 123, deleted 0, read 16253106
0.08 inserts/s, 0.16 updates/s, 0.00 deletes/s, 276.97 reads/s
----------------------------
END OF INNODB MONITOR OUTPUT
============================
答案 0 :(得分：0)
尝试
BEGIN;
SELECT @start := ... LIMIT 1;
SELECT @end := ... LIMIT 1;
UPDATE ...
SET startDate = COALESCE(startDate, @start),
endDate = COALESCE(startDate, @end)
WHERE ...
COMMIT;