Proxy Server Jargon: Decoding Concurrency and Connections

In the use of proxy servers, we often encounter terms such as concurrency, multithreading, and the number of HTTP connections, and the specific meaning of these terms may not be clear to some users. In the following, we will explore the meaning of these keywords in conjunction with the crawler work and explain the relationship between them.

Concurrency is a key concept in proxy server usage and relates to the number of TCP connections that are active during a particular time period. The concept of concurrency is common in operating systems and describes the number of programs or tasks that are running simultaneously in a certain time period. For proxy servers, we usually focus on the number of TCP connections that are active during the same time period.

In the use of proxy IP, each TCP connection represents a communication channel with the target website. For example, if we have 100 proxy IP addresses and use them to establish TCP connections with the target website at the same time, there are 100 concurrent TCP connections running during this time period. Such concurrent connections can speed up the acquisition of data, thereby increasing the efficiency of the crawler.

Multithreading is a concurrent execution technique that allows multiple tasks or operations to be performed simultaneously at the same time. At the software or hardware level, the implementation of multithreading enables the computer to handle multiple tasks at the same time, thus improving the work efficiency and the responsiveness of the system.

In the use of proxy server, multithreading technology is very important. Through multi-threading, we can carry out multiple tasks at the same time, such as using multiple proxy IP to establish a connection with the target website at the same time, so as to achieve concurrent access. This can greatly improve the speed of data acquisition and speed up the execution efficiency of the crawler program.

In multithreaded mode, each thread performs tasks independently without interfering with each other. Such concurrent execution can effectively utilize the multi-core processing power of the computer, assign tasks to different cores for processing, and give full play to the performance of the computer.

①Why do crawler agents experience connection timeouts?

In addition to increasing productivity, multithreading can also improve the responsiveness and user experience of your program. In the scenario of proxy server, if we use a single thread method for data acquisition, it may lead to a slow response of the program, and the user needs to wait a long time to get the result. Through multi-threading, the program can respond to user requests more quickly and provide a better user experience.

The number of HTTP connections refers to the js, css, img, and iframe elements that are loaded when visiting the target web page, and these are counted as HTTP connections. When accessing a web page, the browser needs to establish multiple connections at the same time to load the various elements of the web page, and the number of these connections is the number of HTTP connections.

The relationship between the three is closely related. When we use multithreading technology for crawler work, each thread can independently establish multiple active TCP connections, thus achieving concurrent access. If there is only 1 active TCP connection per thread, then there will be 100 concurrency because there are 100 threads working simultaneously. However, if each thread has many active TCP connections, it is not possible for 100 threads to have only 100 concurrent, or even for a single thread to have 100 concurrent.

②How to choose the right proxy IP service provider

It is important to note that the number of HTTP connections is not only affected by the number of threads, but also by the type of web page visited and the number of elements. In modern dynamic websites, access to a website often requires multiple connections, and the number of connections to visit different websites will also be different.

In crawler work, it is very important to set the number of concurrent, multi-threaded and control the number of HTTP connections reasonably. Reasonable concurrency and multithreading Settings can improve the efficiency of crawlers and speed up data acquisition. At the same time, reasonable control of the number of HTTP connections can avoid the pressure brought by too many connection requests to the target website, thus reducing the risk of being blocked.

In summary, the number of concurrent, multithreaded and HTTP connections is an important factor affecting the efficiency and stability of the crawler. Through reasonable Settings and controls, we can better complete the crawling task, effectively obtain the required data, and ensure the normal operation of the crawling program.