MySQL 5.6 Reference Manual Including MySQL NDB Cluster 7.3-7.4 Reference Guide
To ascertain what your MySQL server is doing, it can be helpful to examine the process list, which indicates the operations currently being performed by the set of threads executing within the server. For example:
mysql> SHOW PROCESSLIST\G
*************************** 1. row ***************************
Id: 1
User: event_scheduler
Host: localhost
db: NULL
Command: Daemon
Time: 2756681
State: Waiting on empty queue
Info: NULL
*************************** 2. row ***************************
Id: 20
User: me
Host: localhost:52943
db: test
Command: Query
Time: 0
State: init
Info: SHOW PROCESSLIST
Threads can be killed with the KILL
statement. See Section 13.7.6.4, “KILL Statement”.