查询取消

概述

每个SelectDB的查询都在一个会话连接中运行，在部分场景下需要终止会话连接，可使用SelectDB提供的SQL查询取消功能，终止会话连接。

使用方式

若需要终止一个查询，可以使用KILL语句终止连接会话，会话中的查询可同时被终止。会话连接的标识符（ID）列表可以通过SHOW PROCESSLIST指令查看，也可以通过SELECT CONNECTION_ID()来查询当前连接会话的标识符。

语法如下。

KILL [CONNECTION | QUERY] processlist_id

使用示例

1. 查看当前连接的Connection ID。

SELECT connection_id();
+-----------------+
| connection_id() |
+-----------------+
| 48              |
+-----------------+
1 row in set (0.00 sec)

2. 查看所有连接的Connection ID。

SHOW PROCESSLIST;
+------------------+------+------+--------------------+---------------------+----------+---------+---------+------+-------+-----------------------------------+---------------------------------------------------------------------------------------+
| CurrentConnected | Id   | User | Host               | LoginTime           | Catalog  | Db      | Command | Time | State | QueryId                           | Info                                                                                  |
+------------------+------+------+--------------------+---------------------+----------+---------+---------+------+-------+-----------------------------------+---------------------------------------------------------------------------------------+
| Yes              |   48 | root | 10.16.xx.xx:44834   | 2023-12-29 16:49:47 | internal | test | Query   |    0 | OK    | e6e4ce9567b04859-8eeab8d6b5513e38 | SHOW PROCESSLIST                                                                      |
|                  |   50 | root | 192.168.xx.xx:52837 | 2023-12-29 16:51:34 | internal |      | Sleep   | 1837 | EOF   | deaf13c52b3b4a3b-b25e8254b50ff8cb | SELECT @@session.transaction_isolation                                                |
|                  |   51 | root | 192.168.xx.xx:52843 | 2023-12-29 16:51:35 | internal |      | Sleep   |  907 | EOF   | 437f219addc0404f-9befe7f6acf9a700 | /* ApplicationName=DBeaver Ultimate 23.1.3 - Metadata */ SHOW STATUS                  |
|                  |   55 | root | 192.168.xx.xx:55533 | 2023-12-29 17:09:32 | internal | test | Sleep   |  271 | EOF   | f02603dc163a4da3-beebbb5d1ced760c | /* ApplicationName=DBeaver Ultimate 23.1.3 - SQLEditor <Console> */ SELECT DATABASE() |
|                  |   47 | root | 10.16.xx.xx:35678   | 2023-12-29 16:21:56 | internal | test | Sleep   | 3528 | EOF   | f4944c543dc34a99-b0d0f3986c8f1c98 | select * from test                                                                    |
+------------------+------+------+--------------------+---------------------+----------+---------+---------+------+-------+-----------------------------------+---------------------------------------------------------------------------------------+
5 rows in set (0.00 sec)

3. 终止正在运行的查询, 正在运行的查询会显示被取消。

KILL QUERY 55;
Query OK, 0 rows affected (0.01 sec)