FastCGI PHP - unable to prematurely close connection to browser

[cactus]

Hi all!

I am optimizing a few of the PHP scripts by:
- doing all that generates output to browser
- closing connection to browser
- doing some more processing

The processing bit cannot be avoided, but the speed of execution (from visitors' point of view) is awesome this way. The problem is that we have tried migrating the script to NginX + FastCGI (it works on Apache + mod_php) but it doesn't close the connection anymore, it keeps it open until the end... Which makes scripts slow again.

I am using Content-Length to allow server to figure out that all content was already generated. This is the test case:

<?
  header("Connection: close"); // not sure we need this one
  header("Content-Encoding: none");
  ignore_user_abort(true);
  ob_start();

  echo ('Lets output something.');

  // output Content-Length and flush buffers:
  $size = ob_get_length();
  header("Content-Length: $size");
  ob_end_flush();
  flush();

  // ****************
  // do some heavy processing here:
  sleep(5);

  function postproc() {
    flush();
    sleep(5);
  }
  register_shutdown_function('postproc');
?>

 
The browser shows this page immediately in Apache+mod_php but it waits for 10 seconds in NginX + FastCGI. 

I am a bit stuck here and would appreciate some help... Is this a problem with FastCGI? Is there another way to do it?

Thanks!

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,51310,51310#msg-51310