First of all, the main functions of allocation are as follows:

1, improve the usability of the application: the server should be used effectively for a long time, but the reality is very unstable, such as the computer will crash, power failure and hardware equipment damage. Using distribution can solve these problems to some extent.

2. Disperse the running pressure of the server, which is also an aspect of improving the usability of the application. For example, if your application has many functions and complex logic, or if you operate a large amount of data, it is difficult or even impossible for a single application or machine to handle your business, then you need to use distribution.

The concept of distribution is actually very simple, that is, one application can't do it or it is difficult to do it, so that multiple applications can do it. It's like asking a person to do something that many people can do. Let's give a simple example in reality, such as building a car. The work of building a car itself can be done by the car factory, but the cost, technology and personnel will increase the production cost, and because the technology is too complicated, one factory can build it. But the cost and difficulty will increase, but it will be divided into several factories to build cars, such as one factory to build engines, one factory to build chassis, one factory to build shells, one factory to build electronic dashboards and so on. Moreover, all the accessories will be distributed to different factories for production, so that each factory can concentrate on doing its own more professional things, which not only reduces costs, but also improves work efficiency.

Back to our web application, generally speaking, a system is an application, and there are various functions in the system, such as the student information management system, which contains various functions, such as user login and authentication, authority configuration and authorization, student information management, student enrollment management, student graduation management, alumni information management and so on. However, when the number of students is particularly large and the internal business logic is particularly complicated, one application may not be able to undertake the normal operation of the system. We can consider using multiple applications in a distributed manner to complete the functions of the system, such as letting one application be responsible for logging in the authentication module, one application handling the authorization function, and the other application handling the contents of student information.

To sum up, distribution is actually a matter to be solved by multiple applications. Distribution is the division of labor in the application layer. For multiple applications on one machine, we call it vertical distribution, and for multiple machines, we call it horizontal distribution. It is relatively simple to realize distribution on one machine, and only memory data sharing between applications is needed. There are many ways to share memory data, such as sharing files with * * * and so on. Multi-computer distribution needs network communication to enjoy data. If it is an application with the same language and technology, you can directly enjoy the memory data. If it is a distributed application in different languages, you need to refer to some commonly used transmission protocol data, such as xml json.