PHP Thread Safe and non ThreadSafe

Original Address http://blog.csdn.net/lrcoop/article/details/45477371

How do I choose the thread safe and non threadsafe version?

The Windows version of PHP from version 5.2.1 started with Threadsafe (thread-safe) and none thread safe (NTS, non-thread-safe) of the points, which is the difference between? 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.

In the first place, it is a thread safe to understand the literal meaning that thread security is performed in order to prevent the new requirements from exhausting system resources by starting the CGI execution of new threads. Non thread safe is non-threaded and does not thread (thread) security checks at execution time.

Therefore, if you are using ISAPI to run PHP must use Threadsafe (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.

Let's look at two ways of executing PHP: ISAPI and fastcgi.

ISAPI execution mode is used in the form of DLL dynamic library, can be executed after the user request, after processing a user request will not disappear immediately, so the need for thread security check, so as to improve the execution efficiency of the program, so if it is to execute PHP with ISAPI, it is recommended to choose thread Safe version;

The fastcgi execution is performed with a single thread, so there is no need for thread security checks, and the removal of thread safety checks can improve execution efficiency, so if PHP is executed in fastcgi, it is recommended to choose the non thread safe version.

PHP Thread Safe and non ThreadSafe