The Windows version of PHP from version 5.2.1 started with the thread safe (thread safe) and none thread safe (NTS, non-thread-safe) of the points, the difference is where? Which one should I use? Here is a simple introduction.
The first Windows version of PHP3.0.17, released on October 20, 2000, started with a thread-safe version, because unlike the Linux/unix system, which works in a multi-process manner, Windows systems work in a multi-threaded way. It is very slow to run PHP as CGI under IIS, because the CGI pattern is built on a multi-process basis, not multithreaded. In general, we will configure PHP to run in ISAPI way, ISAPI is multi-threaded way, so much faster. There is a problem, however, that many commonly used PHP extensions are developed with Linux/unix's multi-process thinking, which can be faulted when running in ISAPI mode. Therefore, the CGI mode under IIS is the safest way to run PHP, but the CGI mode requires reloading and uninstalling the entire PHP environment for each HTTP request, which consumes a huge amount.
To take into account the efficiency and security of PHP under IIS, Microsoft has given the fastcgi solution. FastCGI can allow the PHP process to be reused instead of every new request to re-open a process. FastCGI can also allow several processes to execute simultaneously. This solves the problem that the CGI process pattern consumes too much, and the CGI process pattern does not have the advantage of the thread security problem.
Therefore, if you are using ISAPI to run PHP, you must use the thread safe version, while running PHP in fastcgi mode, there is no need to use thread security, with none thread safe (NTS, non-thread-safe) Version to better improve efficiency.
The difference between thread-safe and non-threading (NTS) security versions of PHP