title: 503 Service Unavailable on PHP process
body: <p>I have a legacy project in Zend 1.12, and when I do an AJAX call to a particular function which I know will take at least a few minutes to run (it's a complicated set of database operations), I get a "503 Service Unavailable" response after a couple of minutes.</p>
  
  <p>The thing is, I know the process ends up finishing, because I have a timestamp column on one of the affected tables that shows an updated timestamp.</p>
  
  <p>I've tried using ini_set on the memory limit to give it a high amount of memory, and I've tried using set_time_limit (setting it at 30 minutes), but I still get back the "HTTP/1.1 503 Service Unavailable" after a couple of minutes.</p>
  
  <p>Now, if it was just me who was going to use the interface for this to run the process on demand, I would have less of an issue with this, but I need it to return what I expect it to return (which is either that it succeeded, or that it failed, and the exception/error that caused it to fail).</p>
  
  <p>Any thoughts on how to prevent it from returning a 503?</p>