title: PHP Sessions stored in MySQL in Ajax heavy environment
body: <p>I'm looking to change my application to store PHP Session data in MySQL.  The application is ajax intensive but does not utilize long-polling or any other type of persistent connection.  </p>
  
  <p>My question is, are there any gotcha's I need to be aware of when writing this code?  For example; I have a page that sends 4 ajax requests to load data (for another topic); will this cause any locking issues if I have to update the session data on every request?</p>
  
  <p>Thanks.</p>