PHP comes with a session hidden Danger (session file exclusive lock causes blocking)

PHP Default Session processor is Session.save_handler = files (that is, file). If the same client concurrently sends multiple requests (such as Ajax sending multiple requests at the same time on the page), and the script executes longer, it can cause the session file to block and affect performance. Because PHP executes session_start () for each request, the file exclusive lock is taken, and the exclusive lock is released only after the request processing has ended. In this way, multiple requests can cause blocking at the same time. The solution is as follows:

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

Author Http://www.lai18.com session_start (); $_session[' test ' = ' test '; Session_write_close (); Do something

(2) using the Session_set_save_handler () function is the implementation of custom session processing.

Author Http://www.lai18.comfunction open ($savePath, $sessionName) {    echo ' open is called ';    return true;} function Close () {    echo ' close is called ';    return true;} function Read ($sessionId) {    echo ' read is called ';    Return ';} function Write ($sessionId, $data) {    echo ' write is called ';    return true;} function Destroy ($SESSIONID) {    echo ' destroy is called ';    return true;} 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.

Author Http://www.lai18.comclass Mysessionhandler extends Sessionhandler  {public     function __construct ()    {    } public     function open ($save _path, $session _id)    {    } public     function close ()    {     } Public     function Create_sid ()    {    } public     function read ($id)    {    } public     function write ($id, $data)    {    }     Public function Destroy ($id)    {    }} $handler = new Mysessionhandler ();//2nd parameter will function session_write_close ()  Register as Register_shutdown_function ()  function. Session_set_save_handler ($handler, true);

Reprint Please specify: Http://blog.csdn.net/hello_katty

PHP comes with a session hidden Danger (session file exclusive lock causes blocking)