Comparison of PHP running methods such as mod_php, FastCGI, PHP-FPM, etc., mod_phpfastcgi_PHP tutorial

Comparison of mod_php, FastCGI, PHP-FPM and other PHP running methods, mod_phpfastcgi

Overview

I wrote this article because today I want to build an LNMP environment under Ubuntu. Nginx uses PHP-FPM, so I have sorted out the interaction between the web server and the PHP interpreter.

As we all know, PHP is a cross-platform and cross-server language, which is one of the reasons why it is so popular. However, not many people know that the PHP interpreter can run in a web server in different ways. The most commonly used way for PHP is to run in Apache as a module (mod_php), which is also the default way for Apache to run PHP. But in Nginx, Nginx uses PHP-FPM.

This article will introduce these concepts. If there is something wrong, please criticize and give me some advice.

What are PHP handlers?

The first thing to remember is that any kind of web server (Apache, Nginx, etc.) is designed to send static resources such as HTML and pictures to users. The web server itself cannot interpret any dynamic scripts (PHP, Python, etc.) wait). The PHP processor is used to interpret the PHP code in the web application, interpret it as HTML or other static resources, and then pass the parsed results to the web server, and finally the web server sends it to the user. Most web servers cannot parse PHP code, so it needs a program that can parse PHP code. This is a PHP processor.

mod_php

First, let’s take a look at running PHP as an Apache module. mod_php is now available in the software repositories of all Linux versions, so it is easy to install.

When PHP runs in Apache as a module, the PHP interpreter is "embedded" in the Apache process. Apache will not call any external PHP process, so this method allows Apache and PHP to communicate better. However, when running PHP in this way, even if Apache only provides static resources (such as HTML), each child process of Apache will load mod_php, resulting in more memory overhead than normal.

Another drawback to running this way is that it only works with Apache. In addition, this method is not suitable for small VPS and large websites, because large websites may have many static resources, and these static resources do not need to be interpreted by the PHP program.

Advantages:
1. Easy to install and update
2. Capacity configuration
Disadvantages:
1. Only works with Apache
2. Increased the memory overhead of Apache sub-process
3. After changing the php.ini file, you need to restart Apache

FastCGI

FastCGI is a common protocol interface between interactive programs and web servers. It is a variant of early CGI (Common Gateway Interface). Compared with CGI, FastCGI reduces the cost of interacting with the Web server and can handle more requests at a time.

Apache can use FastCGI in the form of mod_fcgid. Other web servers such as lighttpd, nginx, Cherokee, and even Microsoft's IIS can also use FastCGI. With FastCGI, multiple versions of PHP can be set up simultaneously, which can be very useful in certain situations.

FastCGI also uses suexec to support different users with their own instances of PHP. This feature is especially important for improving security in shared environments. FastCGI not only ensures performance, but also reduces the memory overhead of the web server.

Advantages:
1. Compatible with most web servers
2. It takes up less memory than mod_php
3. More configuration items, including multi-version PHP and suexec
Disadvantages
1. Complex configuration
2. Not well known by everyone

PHP-FPM(FastCGI Process Manager)

PHP-FPM is the latest way for web servers to use PHP, and it is also another implementation of PHP FastCGI. PHP-FPM is very useful for web applications running on small VPS and multiple servers. At the same time, it can also be used by any Web server that is compatible with FastCGI.

PHP-FPM enables administrators to gracefully stop and start PHP worker processes without losing any queries. This allows us to incrementally update the configuration and binaries without losing any queries. It also allows us to emergency restart the process in case of any unexpected corruption.

Advantages:
1. Compatible with most web servers
2. It takes up less memory than mod_php
3. More configuration items, including multi-version PHP and suexec
Disadvantages
1. Complex configuration
2. Not well known by everyone

Supplement: Four ways for Apache to run PHP

mod_php (DSO, Dynamic Shared Object)
CGI
suPHP
FastCGI

Summary

The content is relatively abstract and I don’t understand it deeply. I will record it for future reference~:)