DeadLock

[yuzd]

#18

in the lastest version , i still get deadlock err:

LATEST DETECTED DEADLOCK

2019-06-12 07:30:16 0x7f95ffb6d700
*** (1) TRANSACTION:
TRANSACTION 31420005, ACTIVE 0 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 7 lock struct(s), heap size 1136, 4 row lock(s)
MySQL thread id 15542, OS thread handle 140282834777856, query id 57808286 172.17.0.2 root Searching rows for update
update hangfire_JobQueue set FetchedAt = UTC_TIMESTAMP(), FetchToken = '97db5d2e-d886-46cc-af80-54fb649c9054' where (FetchedAt is null or FetchedAt < DATE_ADD(UTC_TIMESTAMP(), INTERVAL -1800 SECOND)) and Queue in ('default','apis','recurring') LIMIT 1
*** (1) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 33 page no 3 n bits 88 index PRIMARY of table hangfire.hangfire_JobQueue trx id 31420005 lock_mode X locks rec but not gap waiting
Record lock, heap no 15 PHYSICAL RECORD: n_fields 7; compact format; info bits 0
0: len 4; hex 8000148c; asc ;;
1: len 6; hex 000001df6e38; asc n8;;
2: len 7; hex 32000001811450; asc 2 P;;
3: len 4; hex 80003985; asc 9 ;;
4: len 9; hex 726563757272696e67; asc recurring;;
5: len 5; hex 99a3587790; asc Xw ;;
6: len 30; hex 63633731373138342d626161632d346139322d613339322d316437663532; asc cc717184-baac-4a92-a392-1d7f52; (total 36 bytes);

*** (2) TRANSACTION:
TRANSACTION 31419960, ACTIVE 0 sec updating or deleting
mysql tables in use 1, locked 1
4 lock struct(s), heap size 1136, 8 row lock(s), undo log entries 1
MySQL thread id 15485, OS thread handle 140282217027328, query id 57808157 172.17.0.2 root updating
update hangfire_JobQueue set FetchedAt = UTC_TIMESTAMP(), FetchToken = 'cc717184-baac-4a92-a392-1d7f52b5db74' where (FetchedAt is null or FetchedAt < DATE_ADD(UTC_TIMESTAMP(), INTERVAL -1800 SECOND)) and Queue in ('default','apis','recurring') LIMIT 1
*** (2) HOLDS THE LOCK(S):
RECORD LOCKS space id 33 page no 3 n bits 80 index PRIMARY of table hangfire.hangfire_JobQueue trx id 31419960 lock_mode X
Record lock, heap no 9 PHYSICAL RECORD: n_fields 7; compact format; info bits 0
0: len 4; hex 80001486; asc ;;
1: len 6; hex 000001df6e32; asc n2;;
2: len 7; hex 2c0000027c3024; asc , |0$;;
3: len 4; hex 8000397f; asc 9 ;;
4: len 9; hex 726563757272696e67; asc recurring;;
5: len 5; hex 99a3587790; asc Xw ;;
6: len 30; hex 61333636326665362d663163312d343133392d396639652d343261653036; asc a3662fe6-f1c1-4139-9f9e-42ae06; (total 36 bytes);

do you have any ideas about deadlock?

[tvilkov]

Hi, I also faced some deadlocks and noticed a problem in MySqlJobQueue.cs (line 42):

// Istead of 
using (new MySqlDistributedLock(_storage, "JobQueue", TimeSpan.FromSeconds(30), _options))
// it should be
using (new MySqlDistributedLock(_storage, "JobQueue", TimeSpan.FromSeconds(30), _options).Acquire())
// Otherwise distributed lock is not actually taken and this increases contention on JobQueue table