KILL [TIDB]

The statement KILL TIDB is used to terminate connections in TiDB.

Synopsis

KillStmt ::= KillOrKillTiDB ( 'CONNECTION' | 'QUERY' )? NUM

KillOrKillTiDB ::= 'KILL' 'TIDB'?

Examples

mysql> SHOW PROCESSLIST;
+------+------+-----------+------+---------+------+-------+------------------+
| Id   | User | Host      | db   | Command | Time | State | Info             |
+------+------+-----------+------+---------+------+-------+------------------+
|    1 | root | 127.0.0.1 | test | Query   |    0 | 2     | SHOW PROCESSLIST |
|    2 | root | 127.0.0.1 |      | Sleep   |    4 | 2     |                  |
+------+------+-----------+------+---------+------+-------+------------------+
2 rows in set (0.00 sec)

You can get the TiDB Server details of a session to be killed by querying the INSTANCE column of INFORMATION_SCHEMA.CLUSTER_PROCESSLIST:

SELECT ID, USER, INSTANCE, INFO FROM INFORMATION_SCHEMA.CLUSTER_PROCESSLIST;

+---------------------+------+-----------------+-----------------------------------------------------------------------------+
| ID | USER | INSTANCE | INFO |
+---------------------+------+-----------------+-----------------------------------------------------------------------------+
| 1 | root | 127.0.0.1:10082 | SELECT ID, USER, INSTANCE, INFO FROM INFORMATION_SCHEMA.CLUSTER_PROCESSLIST |
| 2 | root | 127.0.0.1:10080 |  |
+---------------------+------+-----------------+-------------------------------------------------------------
2 rows in set (0.00 sec)

To execute the KILL TIDB statement, connect to the TiDB node where the session needs to be killed:

mysql -h 127.0.0.1 -P 10080 -u root -p

KILL TIDB 2;
Query OK, 0 rows affected (0.00 sec)

MySQL compatibility

• By design, KILL is not compatible with MySQL by default. This helps prevent against a case of a connection being terminated on the wrong TiDB server, because it is common to place multiple TiDB servers behind a load balancer.
• DO NOT set compatible-kill-query = true in your configuration file UNLESS you are certain that clients will be always connected to the same TiDB node. This is because pressing ctrl+c in the default MySQL client opens a new connection in which KILL is executed. If there are proxies in between, the new connection might be routed to a different TiDB node, which possibly kills a different session.
• The KILL TIDB statement is a TiDB extension. The feature of this statement is similar to the MySQL KILL [CONNECTION|QUERY] command and the MySQL command-line ctrl+c feature. It is safe to use KILL TIDB on the same TiDB node.

See also

• SHOW [FULL] PROCESSLIST
• CLUSTER_PROCESSLIST