title: web pages with a lot of AJAX calls performance
body: <p>My project is a web mobile app that uses a lot of <code>AJAX</code> calls to the server, to refresh and retrieve data, I'm using php scripts to get data from the server.</p>
  
  <p>I noticed, and also users told me, that sometimes the application performance is very slow.
  I believe that it's because of the <code>AJAX</code> calls, I checked my server and it doesn't has any performance problems when this problem occurs.</p>
  
  <p>It is very strange, because when the problem occurs, the application send <code>AJAX</code> request to the server and get stuck until the timeout error appear, and when sending it again, it performs perfectly and give an answer in less than a second.</p>
  
  <p>I checked similar issues, and i saw that using <code>php sessions</code> can create file lock and every request needs to wait until the previous ends. 
  This issue cancel the AJAX asynchronous process.
  I am not using sessions but maybe my case is the same and the <code>php scripts</code> perform file lock or other type of locking and cancel the asynchronous.</p>
  
  <p>Anyone has any idea how can I solve this?</p>
  
  <p>Thanks.</p>