Briefly talk about the Reload operation in PHP
Preface
Many seniors have warned us that reload can ensure the smoothness of the entire process. The so-called smoothness means that during the reload process, the old process will There will be no early termination before the current request. For many years, I never questioned this statement until one day, when I reloaded, a 502 error occurred and I had to think again.
How to reproduce the problem? Let us write a simple script to simulate:
1 2 3 4 5 6 |
|
At this time, use a browser to browse this URL, and then immediately perform the reload operation, and you will see 502 error.
Is PHP so weak? Can’t even guarantee the basic smoothness of reload? The answer is of course no. In fact, our goal can be achieved through the
1 |
|
parameters. Unfortunately, this parameter defaults to 0, which means it does not take effect. This article sets it to 10s. Re-execute the previous experimental steps, and this time the results are output normally. However, if you do a few more experiments, you may find that sleep ends immediately when we reload. This is because sleep returns directly after receiving the signal from reload. Let us rewrite the script:
1 2 3 4 5 6 7 8 |
|
Re-execute the previous experimental steps, you will find that the 502 error appears again. This is because although reload causes the first sleep to end immediately, the second sleep is still valid and exceeds the time limit of
1 |
|
. If we set
1 |
|
to 12s, then it's good again.
In this way, we only need to set a reasonable value for
1 |
|
to ensure the smoothness of the reload operation, but what is a reasonable value? If it is too small, it may not be effective. If it is too large, will there be any side effects? Let us repeat the last experiment with questions, but this time we add another monitor:
1 |
|
The purpose of this monitor is to observe the PHP- Regarding the changes in the number of FPM processes, in order to make the effect more obvious, it is recommended to change the startup mode of PHP-FPM to static mode, and at the same time, the number of processes should not be too many.
When we repeated the last experiment, we found that except for the process that was executing the request, other processes were killed directly, and the new process did not start immediately, and it was stuck until the last old process was executed. After that, the new process completes the startup process. During this period, if other requests come in, it will undoubtedly not be responded to immediately.
Based on our experiments, we can conclude that by default, PHP-FPM cannot guarantee smooth execution of the reload operation, and a reasonable
1 |
|
must be set. At the same time, we need to pay attention to However, the value cannot be set too large, otherwise the system may have a more serious request congestion problem.
Summary
The above is all about the Reload operation in PHP. For more related content, please pay attention to the PHP Chinese website (www.php.cn)!

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics











PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.

PHP is widely used in e-commerce, content management systems and API development. 1) E-commerce: used for shopping cart function and payment processing. 2) Content management system: used for dynamic content generation and user management. 3) API development: used for RESTful API development and API security. Through performance optimization and best practices, the efficiency and maintainability of PHP applications are improved.

PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7

PHP is still dynamic and still occupies an important position in the field of modern programming. 1) PHP's simplicity and powerful community support make it widely used in web development; 2) Its flexibility and stability make it outstanding in handling web forms, database operations and file processing; 3) PHP is constantly evolving and optimizing, suitable for beginners and experienced developers.

PHP and Python each have their own advantages, and the choice should be based on project requirements. 1.PHP is suitable for web development, with simple syntax and high execution efficiency. 2. Python is suitable for data science and machine learning, with concise syntax and rich libraries.

PHP and Python have their own advantages and disadvantages, and the choice depends on project needs and personal preferences. 1.PHP is suitable for rapid development and maintenance of large-scale web applications. 2. Python dominates the field of data science and machine learning.

PHP is suitable for web development, especially in rapid development and processing dynamic content, but is not good at data science and enterprise-level applications. Compared with Python, PHP has more advantages in web development, but is not as good as Python in the field of data science; compared with Java, PHP performs worse in enterprise-level applications, but is more flexible in web development; compared with JavaScript, PHP is more concise in back-end development, but is not as good as JavaScript in front-end development.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.
