wait_timeout

Overview

The number of seconds the server waits for activity on a connection before closing it

See also: System Variables for MariaDB Enterprise Server 10.6, in 10.5 ES, in 10.4 ES, in 10.3 ES, in 10.2 ES, in 10.6 CS, in 10.5 CS, in 10.4 CS, in 10.3 CS, and in 10.2 CS

See also: System Variables for MariaDB Enterprise Server 10.6, in 10.5 ES, and in 10.4 ES

USAGE

The wait_timeout system variable can have its default value configured via SkySQL Configuration Manager.

The wait_timeout system variable can be set in a configuration file:

[mariadb]
wait_timeout=120

The global value of the wait_timeout system variable can also be set dynamically at runtime by executing SET GLOBAL:

SET GLOBAL wait_timeout=120;

The session value of the wait_timeout system variable can also be set dynamically at runtime by executing SET SESSION:

SET SESSION wait_timeout=120;

When the wait_timeout system variable is set dynamically at runtime, its value will be reset the next time the server restarts. To make the value persist on restart, set it in a configuration file too.

DETAILS

The wait_timeout system variable sets the time in seconds that the server waits for an idle interactive connection to become active before closing it.

SYNONYMS

SCHEMA

PARAMETERS

Command-line

--wait_timeout=#

Configuration file

Supported

Dynamic

Yes

Scope

Global, Session

Data Type

BIGINT UNSIGNED

Minimum Value

1

Maximum Value

31536000

Product Default Value

28800

SKYSQL

Cloud

SkySQL Topology

ES Ver

Service Default

AWS

Multi-Node Analytics

10.6

28800 (choices: 300, 600, 3600, 28800, 86400)

Single Node Analytics

10.6

28800 (choices: 300, 600, 3600, 28800, 86400)

Replicated Transactions

10.4

600 (choices: 300, 600, 3600, 28800, 86400)

10.5

600 (choices: 300, 600, 3600, 28800, 86400)

10.6

600 (choices: 300, 600, 3600, 28800, 86400)

Single Node Transactions

10.4

600 (choices: 300, 600, 3600, 28800, 86400)

10.5

600 (choices: 300, 600, 3600, 28800, 86400)

10.6

600 (choices: 300, 600, 3600, 28800, 86400)

GCP

Multi-Node Analytics

10.6

28800 (choices: 300, 600, 3600, 28800, 86400)

Single Node Analytics

10.6

28800 (choices: 300, 600, 3600, 28800, 86400)

Replicated Transactions

10.4

600 (choices: 300, 600, 3600, 28800, 86400)

10.5

600 (choices: 300, 600, 3600, 28800, 86400)

10.6

600 (choices: 300, 600, 3600, 28800, 86400)

Single Node Transactions

10.4

600 (choices: 300, 600, 3600, 28800, 86400)

10.5

600 (choices: 300, 600, 3600, 28800, 86400)

10.6

600 (choices: 300, 600, 3600, 28800, 86400)

Cloud

SkySQL Topology

ES Ver

Service Default

AWS

ColumnStore Data Warehouse

10.6

28800 (choices: 300, 600, 3600, 28800, 86400)

Enterprise Server With Replica(s)

10.4

600 (choices: 300, 600, 3600, 28800, 86400)

10.5

600 (choices: 300, 600, 3600, 28800, 86400)

10.6

600 (choices: 300, 600, 3600, 28800, 86400)

Enterprise Server Single Node

10.4

600 (choices: 300, 600, 3600, 28800, 86400)

10.5

600 (choices: 300, 600, 3600, 28800, 86400)

10.6

600 (choices: 300, 600, 3600, 28800, 86400)

GCP

ColumnStore Data Warehouse

10.6

28800 (choices: 300, 600, 3600, 28800, 86400)

Enterprise Server With Replica(s)

10.4

600 (choices: 300, 600, 3600, 28800, 86400)

10.5

600 (choices: 300, 600, 3600, 28800, 86400)

10.6

600 (choices: 300, 600, 3600, 28800, 86400)

Enterprise Server Single Node

10.4

600 (choices: 300, 600, 3600, 28800, 86400)

10.5

600 (choices: 300, 600, 3600, 28800, 86400)

10.6

600 (choices: 300, 600, 3600, 28800, 86400)

PRIVILEGES

The wait_timeout system variable requires the SUPER privilege to dynamically set its global value at runtime.

The wait_timeout system variable does not require any special privilege to dynamically set its session value at runtime.

EXAMPLES

Effect from Interactive Timeout

The interactive_timeout system variable works by overriding the value of the wait_timeout system variable for interactive connections. This can be demonstrated by setting interactive_timeout and wait_timeout to different values:

SET GLOBAL interactive_timeout=60;

SET GLOBAL wait_timeout=30;

With this configuration, if a user connects to the server with an interactive client, then they will see that their session's value of the wait_timeout system variable is actually set to the global value of interactive_timeout. The mysql command-line client functions as an interactive client by default, so this client can be used to demonstrate the behavior of interactive clients:

$ sudo mysql

SHOW SESSION VARIABLES LIKE 'wait_timeout';

+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout  | 60    |
+---------------+-------+

However, the mysql command-line client functions as a non-interactive client if the --batch option is provided, so this client can be used with this option to demonstrate the behavior of non-interactive clients:

$ sudo mysql --batch --execute="SHOW SESSION VARIABLES LIKE 'wait_timeout'"
Variable_name   Value
wait_timeout    30

Aborted Connections

If a connection has been idle for longer than the configured value of the wait_timeout system variable, then the server will kill the connection. If the log_warnings system variable is set to 2 or more, then a warning with the ER_ABORTING_CONNECTION error code will be written to the error log:

Feb 20 02:16:58 ip-172-30-0-123 mysqld: 2020-02-20  2:16:58 16 [Warning] Aborted connection 16 to db: 'unconnected' user: 'root' host: 'localhost' (Got timeout reading communication packets)

Dynamically Resetting Global Value to Default

The global value of the wait_timeout system variable can be dynamically reset to the default value by setting it to DEFAULT:

SET GLOBAL wait_timeout=180;

SHOW GLOBAL VARIABLES LIKE 'wait_timeout';

+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout  | 180   |
+---------------+-------+

SET GLOBAL wait_timeout=DEFAULT;

SHOW GLOBAL VARIABLES LIKE 'wait_timeout';

+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout  | 28800 |
+---------------+-------+

Resetting Session Value to Global Value

The session value of the wait_timeout system variable can be reset to the global value by setting it to DEFAULT:

SET SESSION wait_timeout=180;

SHOW GLOBAL VARIABLES LIKE 'wait_timeout';

+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout  | 28800 |
+---------------+-------+

SHOW SESSION VARIABLES LIKE 'wait_timeout';

+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout  | 180   |
+---------------+-------+

SET SESSION wait_timeout=DEFAULT;

SHOW SESSION VARIABLES LIKE 'wait_timeout';

+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout  | 28800 |
+---------------+-------+

Invalid Value for Variable

If a user tries to set the wait_timeout system variable to an invalid value, then the specific behavior depends on the value of the sql_mode system variable.

If the sql_mode system variable does not contain STRICT_ALL_TABLES and a user tries to set the wait_timeout system variable to an invalid value, then the operation will appear to succeed, but a warning will be raised with the ER_TRUNCATED_WRONG_VALUE error code. The warning will point out that the value was truncated, which means that the value was automatically set to the closest invalid value:

SET GLOBAL wait_timeout=-1;

SHOW WARNINGS;

+---------+------+----------------------------------------------+
| Level   | Code | Message                                      |
+---------+------+----------------------------------------------+
| Warning | 1292 | Truncated incorrect wait_timeout value: '-1' |
+---------+------+----------------------------------------------+

SHOW GLOBAL VARIABLES LIKE 'wait_timeout';

+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout  | 1     |
+---------------+-------+

SET GLOBAL wait_timeout=31536001;

SHOW WARNINGS;

+---------+------+----------------------------------------------------+
| Level   | Code | Message                                            |
+---------+------+----------------------------------------------------+
| Warning | 1292 | Truncated incorrect wait_timeout value: '31536001' |
+---------+------+----------------------------------------------------+

SHOW GLOBAL VARIABLES LIKE 'wait_timeout';

+---------------+----------+
| Variable_name | Value    |
+---------------+----------+
| wait_timeout  | 31536000 |
+---------------+----------+

If the sql_mode system variable does contain STRICT_ALL_TABLES and a user tries to set the wait_timeout system variable to an invalid value, then the operation will fail with the ER_WRONG_VALUE_FOR_VAR error code:

SHOW SESSION VARIABLES LIKE 'sql_mode';

+---------------+-------------------------------------------------------------------------------------------+
| Variable_name | Value                                                                                     |
+---------------+-------------------------------------------------------------------------------------------+
| sql_mode      | STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
+---------------+-------------------------------------------------------------------------------------------+

SET SESSION sql_mode=CONCAT(@@session.sql_mode, ',STRICT_ALL_TABLES');

SET GLOBAL wait_timeout=-1;

ERROR 1231 (42000): Variable 'wait_timeout' can't be set to the value of '-1'

Invalid Type for Variable

If a user tries to set the wait_timeout system variable to an invalid argument, then the operation will fail with the ER_WRONG_TYPE_FOR_VAR error code:

SET GLOBAL wait_timeout='';

ERROR 1232 (42000): Incorrect argument type to variable 'wait_timeout'

SET GLOBAL wait_timeout='infinity';

ERROR 1232 (42000): Incorrect argument type to variable 'wait_timeout'

ERROR HANDLING

FEATURE INTERACTION

RESPONSES

DIAGNOSIS

ISO 9075:2016

CHANGE HISTORY

Release Series

History

10.6 Enterprise

  • Present starting in MariaDB Enterprise Server 10.6.4-1.

10.6 Community

  • Present starting in MariaDB Community Server 10.6.0.

10.5 Enterprise

  • Present starting in MariaDB Enterprise Server 10.5.3-1.

10.5 Community

  • Present starting in MariaDB Community Server 10.5.0.

10.4 Enterprise

  • Present starting in MariaDB Enterprise Server 10.4.6-1.

10.4 Community

  • Present starting in MariaDB Community Server 10.4.0.

10.3 Enterprise

  • Present starting in MariaDB Enterprise Server 10.3.16-1.

10.3 Community

  • Present starting in MariaDB Community Server 10.3.0.

10.2 Enterprise

  • Present starting in MariaDB Enterprise Server 10.2.25-1.

10.2 Community

  • Present starting in MariaDB Community Server 10.2.0.

Release Series

History

10.6 Enterprise

  • Present starting in MariaDB Enterprise Server 10.6.4-1.

10.5 Enterprise

  • Present starting in MariaDB Enterprise Server 10.5.3-1.

10.4 Enterprise

  • Present starting in MariaDB Enterprise Server 10.4.6-1.

EXTERNAL REFERENCES