Solution to blocking problem caused by exclusive lock of PHP session file

This article mainly introduced the PHP session file exclusive lock to cause congestion, this article explains PHP using the default file sessions processor easy to lead to blocking problem solving method, the need for friends can refer to the

The default session processor for PHP is Session.save_handler = files (i.e. file). If the same client concurrently sends multiple requests (such as Ajax sending multiple requests at the same time), and the script executes longer, it can cause the session file to block and affect performance. Because PHP executes session_start () for each request, it obtains a file exclusive lock that will not be released until the request processing is complete. In this way, multiple requests can cause blocking at the same time. The solution is as follows:

(1) After modifying the session variable, immediately use Session_write_close () to save the session data and release the file lock.

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Session_Start (); $_session[' test ' = ' test ';   Session_write_close (); Do something

(2) using the Session_set_save_handler () function is to implement custom session processing.

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function open ($savePath, $sessionName) {echo ' Open is called ';   function Close () {echo ' close are called '; return true;}   function Read ($sessionId) {echo ' read is called ';   function Write ($sessionId, $data) {echo ' write is called ';   function Destroy ($SESSIONID) {echo ' destroy is called ';   Function GC ($lifetime) {echo ' GC is called '; return true;} Session_set_save_handler ("Open", "close", "read", "write", "Destroy", "GC");   Register_shutdown_function (' Session_write_close ');   Session_Start (); $_session[' foo '] = "bar";

Of course, after PHP 5.4.0, you can use it by implementing the Sessionhandlerinterface interface or inheriting the Sessionhandler class.

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Class Mysessionhandler extends Sessionhandler {public Function __construct () {} Public Function open ($save _path, $se ssion_id) {} public Function Close () {} public Function Create_sid () {} public function read ($id) {} public   function Write ($id, $data) {} Public function destroy ($id) {}} $handler = new Mysessionhandler (); The 2nd parameter registers the function Session_write_close () as the Register_shutdown_function () function. Session_set_save_handler ($handler, true);

You can implement and encapsulate the above code, using MySQL or other memory databases to manage session data. can also solve the use of cluster

, session data sharing is a problem.