What is the number of mysql connections?

The number of mysql connections refers to the number of clients that can connect to the MySQL server simultaneously within a certain period of time. The following factors need to be considered when setting the number of connections: 1. Hardware resources. If the server's hardware resources are low, the number of connections needs to be lowered accordingly; 2. Application requirements. For applications with fewer concurrent requests, lower connections The number may be sufficient; 3. The number of concurrent queries. If there are many concurrent queries, the number of connections needs to be increased accordingly; 4. Long connections and short connections. Long connections can reduce the need for the number of connections, but may cause the connection status to occupy too many resources. .

The operating environment of this article: Windows 10 system, MySQL version 8.0.32, Dell g3 computer.

The number of mysql connections refers to the number of clients that can connect to the MySQL server simultaneously within a certain period of time. Each client requires a database connection to communicate with the server. The setting of the number of connections has an important impact on key aspects such as the performance and availability of the MySQL server.

In MySQL, the configuration of the number of connections is mainly divided into two parameters: the maximum number of connections (max_connections) and the current number of active connections (threads_connected). The maximum number of connections refers to the maximum number of connections that the MySQL server can handle simultaneously, while the current number of active connections refers to the number of connections in use.

Why is the number of connections important?

The number of connections is very important in high-concurrency scenarios, which affects the performance and availability of the database server. Setting the number of connections too low may cause the server to be unable to handle all connection requests, resulting in request timeouts or connection errors. Setting it too high may cause excessive server resource consumption, and the server may crash when faced with a large number of connection requests.

How to set a reasonable number of connections?

Setting a reasonable number of connections requires comprehensive consideration of the following factors:

1. Hardware resources: The hardware resources of the database server limit the concurrency that can be supported Number of connections. For example, CPU processing power, memory size and disk IO all have an impact on the number of connections. If the server's hardware resources are low, the number of connections needs to be reduced accordingly.

2. Application requirements: The access pattern of the application to the database and the number of concurrent requests are another important factor in determining the number of connections. For applications that require frequent access to the database, a higher number of connections may be necessary, while for applications with fewer concurrent requests, a lower number of connections may be sufficient.

3. Number of concurrent queries: MySQL is a multi-threaded database server. Each query request needs to obtain a connection from the connection pool, process the request and release the connection. If there are many concurrent queries, the number of connections needs to be increased accordingly.

4. Long connections and short connections: Long connections and short connections also have an impact on the number of connections required. A long connection means that the application maintains a connection to the database for a period of time, while a short connection means that a new connection is established for each query request. Long connections can reduce the number of connections required, but may cause the connection state to occupy too many resources.

When determining a reasonable number of connections, you can use some monitoring tools to view the current number of connections and make adjustments according to the actual situation. In addition, you can also improve the performance of the database server and reduce dependence on the number of connections by optimizing SQL queries, increasing cache, and improving hardware performance.

Summary:

The number of connections is the number of concurrent connections that the MySQL database server can handle within a certain period of time. Properly setting the number of connections is critical to the performance and availability of the database server. Factors such as hardware resources, application requirements, number of concurrent queries, and connection types need to be considered to determine a reasonable number of connections. At the same time, we reduce dependence on the number of connections by optimizing SQL queries, increasing cache, and improving hardware performance, thereby improving the performance of the database server.

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