To debug InnoDB lock waits for transaction or show how many rows are locked (look under transaction):

To debug InnoDB lock waits for transaction or show how many rows are locked (look under transaction):

Method 1:

SELECT * FROM INFORMATION_SCHEMA.INNODB_TRX;

https://dev.mysql.com/doc/refman/5.5/en/innodb-information-schema-transactions.html

Method 2:

Enabling the InnoDB Lock Monitor

To enable the InnoDB Lock Monitor for periodic output, create the innodb_lock_monitor table:

CREATE TABLE innodb_lock_monitor (a INT) ENGINE=INNODB;

To disable the InnoDB Lock Monitor, drop the table:

DROP TABLE innodb_lock_monitor;

As of MySQL 5.6.16, you can also enable the InnoDB Lock Monitor by setting the innodb_status_output_locks system variable to ON. As with the CREATE TABLE method for enabling InnoDB Monitors, both the InnoDB standard Monitor and InnoDB Lock Monitor must be enabled to have InnoDBLock Monitor data printed periodically:

set GLOBAL innodb_status_output=ON;
set GLOBAL innodb_status_output_locks=ON;

When you shut down the server, the innodb_status_output and innodb_status_output_locks variables are set to the default OFF value.

To disable the InnoDB Lock Monitor, set innodb_status_output_locks to OFF. Set innodb_status_output to OFF to also disable the standard InnoDB Monitor.

Note: To enable the InnoDB Lock Monitor for SHOW ENGINE INNODB STATUS output, you are only required to enable innodb_status_output_locks.

https://dev.mysql.com/doc/refman/5.6/en/innodb-enabling-monitors.html

Method 3:

Run MySQL command in shell under console:

# mysql -u root -p -e 'SHOW ENGINE INNODB STATUS\G'

------------
TRANSACTIONS
------------
Trx id counter 381
Purge done for trx's n:o < 37F undo n:o < 0
History list length 39
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0, not started
MySQL thread id 84, OS thread handle 0x7f5b66aff700, query id 975 localhost root
SHOW ENGINE INNODB STATUS
---TRANSACTION 0, not started
MySQL thread id 50, OS thread handle 0x7f5b66c23700, query id 838 192.168.6.112 jun
---TRANSACTION 32E, not started
MySQL thread id 33, OS thread handle 0x7f5b8c04a700, query id 693 192.168.6.112 jun
---TRANSACTION 35F, not started
MySQL thread id 31, OS thread handle 0x7f5b66c6c700, query id 518 192.168.6.112 jun
---TRANSACTION 340, not started
MySQL thread id 28, OS thread handle 0x7f5b66bda700, query id 381 192.168.6.112 jun
---TRANSACTION 380, ACTIVE 1 sec starting index read
mysql tables in use 2, locked 2
LOCK WAIT 2 lock struct(s), heap size 376, 1 row lock(s)
MySQL thread id 83, OS thread handle 0x7f5b66b91700, query id 973 127.0.0.1 go_erp statistics
SELECT   SO.idOrder , SOLine.changed , SOLine.orderQty FROM SO INNER JOIN SOLine ON SO.idOrder = SOLine.idOrder WHERE SO.idOrder = 1 ORDER BY SO.idOrder FOR UPDATE
------- TRX HAS BEEN WAITING 1 SEC FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 0 page no 323 n bits 72 index `PRIMARY` of table `go_erp`.`SO` trx id 380 lock_mode X locks rec but not gap waiting
------------------
---TRANSACTION 37F, ACTIVE 2 sec
5 lock struct(s), heap size 1248, 3 row lock(s), undo log entries 1
MySQL thread id 82, OS thread handle 0x7f5b66b48700, query id 969 127.0.0.1 go_erp

----------------------------

Method 4:

Install innotop:

# yum install innotop

Reference:

https://dev.mysql.com/doc/refman/5.5/en/innodb-information-schema-transactions.html

https://dev.mysql.com/doc/refman/5.5/en/innodb-trx-table.html

http://www.xaprb.com/blog/2007/09/18/how-to-debug-innodb-lock-waits/