Use the KILL statement to end SQL statements and connections - PolarDB

Stops a running SQL statement or terminates a database connection in PolarDB-X 1.0.

Prerequisites

Before you begin, ensure that you have:

A PolarDB-X 1.0 instance
An active connection to the PolarDB-X 1.0 database (see Step 4: Connect to PolarDB-X)

How it works

PolarDB-X routes SQL through two layers: a logical layer that manages client connections, and a physical layer that executes SQL on the underlying storage nodes. The KILL statement targets each layer differently:

Statement	Effect
`KILL PROCESS_ID`	Stops all logical and physical SQL on a connection, then closes the connection
`KILL 'PHYSICAL_PROCESS_ID'`	Stops a specific physical SQL statement without affecting the connection
`KILL 'ALL'`	Stops all running physical SQL statements in the database

PolarDB-X 1.0 does not support KILL QUERY. In standard MySQL, KILL QUERY stops the current statement while keeping the connection open. In PolarDB-X 1.0, use KILL PROCESS_ID to stop a connection and all its associated SQL, or KILL 'PHYSICAL_PROCESS_ID' to stop a specific physical statement.

Stop a connection

To stop all SQL on a connection and close it, run:

KILL PROCESS_ID

Get PROCESS_ID by running SHOW [FULL] PROCESSLIST.

Example workflow:

List active connections and find the target process:
```
SHOW FULL PROCESSLIST;
```
Use the Id value from the output to stop the connection:
```
KILL 100;
```

Stop a physical SQL statement

To stop a specific physical SQL statement without closing the connection, run:

KILL 'PHYSICAL_PROCESS_ID'

Get PHYSICAL_PROCESS_ID by running SHOW PHYSICAL_PROCESS_ID.

PHYSICAL_PROCESS_ID is a string, not a number. Always enclose the value in single quotation marks.

Example:

mysql> KILL '0-0-521570';
Query OK, 0 rows affected (0.01 sec)

Stop all physical SQL statements

To stop all running physical SQL statements in the database, run:

KILL 'ALL'