title: can a PHP $_SESSION survive a website crash
body: <p>I know this is a really vague question, but I was wondering how much a $_SESSION variable can handle in terms of stress. If a $_SESSION is like a cookie, then once a user clears his or her cookies from the browser then the $_SESSION should be destroyed. Also, if session_destroy() is called then the $_SESSION variable will be destroyed.</p>
  
  <p><strong>Are there other instances where a $_SESSION variable can be destroyed, like maybe a website crash?</strong> If PHP is overloaded on a website, does it directly have to affect the $_SESSION or any other functions and variables dealing with it, or does it affect everything as a whole?</p>
  
  <p><strong>Why am I asking?</strong> 
  I'm almost finished writing an abandoned cart script for my ecommerce site and I wanted to redirect the customers back to the site where their order will still be saved in a $_SESSION. The only way the $_SESSION can be destroyed is if the customer completes the purchase. Of course, the customer can also clear the cookies on his or her browser.</p>
  
  <p>But I'm wondering if there is another instance where the $_SESSION can be destroyed aside from those two mentioned above. </p>
  
  <p>A lot of abandoned cart systems store the order info into a database and include that into the email the user receives so they can see the order inside the email. Sure I can write the order into a database, but it's easier to just retain everything in a $_SESSION and have the customer return to the site with their order still in an active $_SESSION.</p>
  
  <p><strong>What can a $_SESSION survive?</strong></p>