How to set the number of MySQL connections

MySQL connection number settings

By default, the maximum number of connections allowed by MySQL is 151. This may be enough for a small website or application, but when many users are connecting at the same time, this number of connections will not be enough to meet the needs of the application. To set the number of MySQL connections, you can set it in the MySQL configuration file.

Step 1: Find the my.cnf file

To modify the number of MySQL connections, you first need to find the my.cnf file. In Linux systems, my.cnf is located in the /etc/ directory. Open the my.cnf file using the command line editor:

sudo nano /etc/my.cnf

Step 2: Set the maximum number of connections

in the my.cnf file , find the following line:

max_connections=151

Here you can change "151" to the desired number of connections. Generally, you need to consider the following factors to determine the number of connections required:

How much memory and CPU resources each connection of the application needs to consume

How much memory is available to the MySQL server

Hardware resources for MySQL servers and applications

In general, you can calculate the ideal maximum number of connections based on the memory size on the server using the following formula:

(Available memory Total - Total memory used by MySQL) ÷ Memory required per connection = Maximum number of connections

Taking these factors into account, you should set a reasonable maximum number of connections.

Step 3: Save changes and restart MySQL

When you have finished changing the my.cnf file, save and exit the editor. You will then need to restart the MySQL process for the changes to take effect:

sudo service mysql restart

This will restart the MySQL server so that you can use the modified maximum number of connections.

How to Optimize the Number of Connections

Once you have completed configuring the number of MySQL connections appropriately, it is possible that you wish to further optimize the connections to improve performance. Here are some tips for optimizing the number of connections:

Connection pooling is a widely used technology that can share MySQL connections among multiple requests. This method reduces the overhead of connection creation, teardown, and release. Built-in connection pooling support is a feature of many high-level programming languages, and in addition, third-party connection pooling libraries can also be used.

Reduce the use of long-lived connections: A long-lived connection is a connection that can be reused between multiple requests. Persistent connections in the MySQL process consume resources, although they can improve performance, even when the connection is inactive. Avoiding too many persistent connections is key to optimizing the number of connections.

When the database environment is under high load, consider using read-write separation technology to distribute read-only operations to multiple slave servers. This reduces the load on the main server and improves response speed and throughput.

The above is the detailed content of How to set the number of MySQL connections. For more information, please follow other related articles on the PHP Chinese website!