#StackBounty: #mysql #mysql-5.6 #deadlock MySQL 5.6.34 RDS Warning: a long semaphore wait causes crash — log included

Bounty: 150

I had my RDS MySQL 5.6.34 server crash under normal load with nothing out of the ordinary today (That I could find). Amazon support pointed me the the error log.

MySQL config:

You can see full error log at:


Most of the error log has:

InnoDB: Warning: a long semaphore wait:
–Thread 47504778909440 has waited at dict0dict.cc line 1122 for 241.00 seconds the semaphore:
Mutex at 0x2b33b16f34a8 created file dict0dict.cc line 1057, lock var 1
waiters flag 1
InnoDB: Warning: a long semaphore wait:

There is deadlock too

2018-07-05 23:11:31 2b34c9f8d700
TRANSACTION 1056966456, ACTIVE 0 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 22 lock struct(s), heap size 2936, 10 row lock(s), undo log entries 8
MySQL thread id 149979681, OS thread handle 0x2b348aea9700, query id 1268732633 phppoint updating
UPDATE `phppos_items` SET `last_modified` = '2018-07-05 18:11:31'
WHERE `item_id` = 9794
RECORD LOCKS space id 0 page no 1273297 n bits 152 index `PRIMARY` of table `phppoint_fatpanda`.`phppos_items` trx id 1056966456 lock_mode X locks rec but not gap waiting
Record lock, heap no 30 PHYSICAL RECORD: n_fields 61; compact format; info bits 0
 0: len 4; hex 80002642; asc   &B;;
 1: len 6; hex 00003f00027d; asc   ?  };;
 2: len 7; hex 1b00013aea2ab2; asc    : * ;;
 3: len 24; hex 4650205468757273646179204368756262792050726f6d6f; asc FP Thursday Chubby Promo;;
 4: len 4; hex 80000041; asc    A;;

Any idea of where I can start looking?

Get this bounty!!!

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