Web server summarizes _php instances using PHP to generate Web pages in three ways

Found on the MySQL help document when looking for Mysql_pconnect, here.

Web server uses PHP to generate a Web page of three of the following three kinds:

One: PHP as a CGI wrapper. in this way, each request to the Web server will cause a PHP parser process to be created, and the PHP parser process terminates when the PHP page executes.

two: In a multi-process Web server, PHP is used as a module of the Web server. This is the most popular practice at the moment, but it is only apahce in this way at present. A multiple-process Web server usually has a total parent process that coordinates a bunch of child processes to work. When a page request arrives in the Web server, the parent process hands the request to an idle subprocess to complete. Two requests for the same client are not necessarily handled by the child process of the same Web server.

three: In a multi-threaded Web server, PHP as a plug-in. For example, IIS uses this method. It works as much as a process, but it uses threads rather than processes.