Introduction to Web System performance testing terminology

Concurrent users

Concurrency is generally divided into two situations. One is the strict concurrency, that is, all users do the same thing or operation at the same time. This operation generally refers to the same type of business, such as in the credit card approval business, a certain number of users at the same time to the completed approval of the business to submit. There is also a special case where all users do exactly the same thing, for example, in a credit card approval business, all users can apply for business together, or modify the same record. Another concurrency is generalized range of concurrency. The difference between this concurrency and the previous concurrency is that although multiple users have made requests or performed actions on the system, these requests or actions can be the same or different. For the whole system, there are still many users working on the system at the same time, and therefore also belong to the concurrency category.
As you can see, the latter concurrency is the one that contains the previous concurrency. and the latter concurrency is closer to the actual use of the user, so for most systems, only a small number of users, or rarely, "concurrency in strict sense."

Concurrent Quantity

Concurrent quantity refers to the number of simultaneous requests. There are two common misconceptions about the number of concurrent users. One of the misconceptions is that the number of concurrent users is understood as the number of users who use the system, on the grounds that they may use the system at the same time, and that a more near-correct view is that the number of online users is understood as the number of concurrent users. The fact that online users are not necessarily associated with other users, such as users who are browsing the web, has no effect on the server, but the number of online users is one of the main bases for calculating the number of concurrent users.

Request Response Time

Refers to the time at which the client makes a request to the entire process of getting a response. In some tools, the request response time is usually written as "tllb", or "time to Last byte", which means the amount of times it takes to start a request to the client to receive the last byte. The unit of the request response time process is typically "seconds" or "milliseconds".

Transaction response Time

A transaction may consist of a series of requests, and the response time of a transaction is primarily for the user, and is a macro concept that is presented to the user in order to explain the business response time. For example, the response time for a cross-line withdrawal transaction is made up of a series of requests.

Throughput

Refers to the sum of the amount of data transmitted over the network during a performance test. Throughput/Transfer time is the throughput rate.

Tps

Transactionper second, the number of transactions or transactions that the system can process per second. It is an important indicator to measure the system's processing ability.

Hits

HPS, the number of HTTP requests that the user submits to the Web server per second. This indicator is a unique indicator of Web application: The Web application is a "request-response" mode, the user makes one request and the server is processed once, so click is the smallest unit of the transaction that the Web app can handle. If you define each click as a trade, CTR and TPS are a concept. It is easy to see that the greater the CTR, the greater the pressure on the server. CTR is just a performance reference, and it's important to analyze the impact of clicks. Note that the Click here does not refer to a single click of the mouse. Because in a single click, the client may make multiple HTTP requests to the server.

Resource utilization

Refers to the use of different system resources, such as server CPU utilization, disk utilization, and so on. Resource utilization is the main basis for analyzing system performance Index and improving performance, so it is the focus of Web performance testing work. Resource utilization is mainly for Web server, operating system, database server, network, etc., which is the main reference for testing and analyzing bottleneck. In the Web performance test, it is more necessary to collect the corresponding parameters for analysis.

Introduction to Web System performance testing terminology