The difference between long and short connections in PHP

When using PHP for network programming, you often hear the concepts of "long connection" and "short connection". Long connection and short connection refer to two different ways to establish a connection under the TCP protocol. These two ways have different advantages and applicable occasions. The following is a detailed introduction and comparison of these two connection methods.

1. Long connection

The so-called long connection means that after a connection is established, the connection between the client and the server remains valid for a long time until one party completes the sending or an error occurs midway. Disconnect. The advantage of this method is that the connection process consumes a lot of money, but during the process of maintaining the connection, the data transmission efficiency is high, and there is no need to repeat the operation of establishing and disconnecting the connection, which reduces the consumption of network traffic and system resources. For applications that require high-frequency interaction, large amounts of data, and high real-time requirements, using long connections is very advantageous.

In addition, long connections can also set up a real-time heartbeat mechanism. Once data transmission is interrupted, a heartbeat will be sent immediately, and abnormal connections will be discovered and restored in a timely manner, thereby ensuring the reliability and stability of data transmission.

2. Short connection

The so-called short connection means that after completing a data transfer, the client and the server actively close the connection. Compared with long connections, the advantages of short connections are that the connection is established quickly and takes up less system resources. The disadvantage is that the connection needs to be established and closed frequently, which increases network traffic and system overhead.

Short connections are suitable for scenarios where a single data transmission is small, such as http requests, etc. In HTTP requests, the connection needs to be re-established for each request, but since HTTP requests have less data, the resource consumption of short connections is also relatively small.

3. Comparison between long connections and short connections

From the perspective of the number of connection establishment and disconnection times, long connections are compared with short connections because they only need to be established once during the initial connection. Keeping connections valid for a long time saves time and resources in establishing and disconnecting connections, allowing for more efficient data transfer. However, since long connections occupy system resources, not releasing resources for a long time may also affect the stability and performance of the system.

For short connections, since each connection needs to be re-established and destroyed, a certain amount of network traffic and system overhead will be increased. However, for scenarios where a single data transmission is small, the resource consumption is relatively small.

4. How to choose between long and short connections

For applications that require frequent interaction, using long connections can effectively reduce the establishment and release of connections and improve data transmission efficiency. At the same time, by setting up a real-time heartbeat mechanism, the stability and reliability of the connection can be ensured.

For applications with less single data transmission and large request volume, using short connections can effectively reduce network traffic and system resource consumption. In short connections, the connection pool mechanism can also be used to optimize the allocation and use of connection resources and improve performance and stability.

In summary, long connections and short connections each have their own advantages and disadvantages, and you need to choose which method to use based on the specific application scenario.

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