mysql timeout settings

MySQL is an open source relational database management system. Used to store and manage data, suitable for a variety of different sizes and types of applications. When using MySQL, some problems may occur, such as connection timeout. This article will discuss how to set timeouts in MySQL.

What is MySQL connection timeout?

MySQL connection timeout refers to the disconnection caused by the connection duration being too long. If the MySQL connection duration exceeds the preset time, the connection will be automatically disconnected. For example, if your application needs to establish a connection to a database and perform a query, but the server is not responding, the connection is automatically disconnected.

Causes of MySQL connection timeout

MySQL connection timeout may be caused by a variety of reasons. The following are some possible reasons:

1. Abnormal situations such as network interruption during query request sending.
2. The connection occupies too many resources and causes timeout, such as busy queries, connection waiting for locks, etc.
3. The MySQL server or client has set a connection timeout.
4. The database server load is too high and cannot respond to client requests in time.

How to set MySQL connection timeout?

MySQL connection timeout can be set on the MySQL client or server.

Set the connection timeout on the MySQL client

mysql --connect_timeout=60 --user=username --password=yourpassword dbname

In the above code, the --connect_timeout option sets the connection timeout to 60 seconds. If no connection is established within 60 seconds, the connection will be automatically disconnected. The --user and --password options are used to specify the username and password. dbname is the name of the database to be connected.

Set the connection timeout on the MySQL server

On the MySQL server, the connection timeout can be set in the following two ways:

1. Through the system variable max_allowed_packet

The max_allowed_packet system variable on the MySQL server specifies the maximum packet size received by the MySQL server. If an attempt is made to send a packet that exceeds this size, the connection will be dropped. The max_allowed_packet variable can be set in MySQL's configuration file or changed at runtime via the SET command.

2. Through the wait_timeout variable

The wait_timeout variable specifies the time that the MySQL server can wait when there are no active client connections. If the wait_timeout variable is set to 0, it means there is no timeout limit. The default value of wait_timeout is 8 hours. The wait_timeout variable can be set in MySQL's configuration file or changed at runtime via the SET command.

It should be noted that modifying system variables may have an impact on the performance and security of the MySQL server, so it is recommended to consider carefully before modifying. It is best to make modifications in a test environment and be sure to back up the modifications.

Summary

MySQL connection timeout is a common problem, but by setting the timeout correctly, this problem can be effectively solved. The connection timeout can be set on the MySQL client or server, and can be adjusted appropriately according to application scenarios and needs. At the same time, pay attention to the possible impact of modifying system variables, and do backup and testing work.

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