Description:
------------
The problem is that I have a script which is called twice by the same brother using a Http connection with the Keep Alive attibute.

For the first call: 

I notify the end of the answer as follow:
===========================================
ignore_user_abort(true);
$msg="toto";
header("Content-Length: ".strlen($msg));
echo $msg;
flush();
... some long time stuff here=
===========================================
the browser read the answer and then I ask again for the same page using the same tcp connection (Keep-alive). 

In the second call, the output is blocked until the first call process is dead. Thus its execution is suspended until the "long time stuff" is done. (I see the http request using tcpdump). 



If I put the following for the first call:

====================================================
header("Cache-Control: no-cache, must-revalidate");
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Connection: close");

$msg="toto";
header("Content-Length: ".strlen($msg));
echo $msg;
flush();
=====================================================

then all work fine except that the connection is effectively closed by the browser and then re-open which implies a great lost of performances.

Also I did not find any mechanism (bug?) in php to indicate that the response is done. (like http_close or fclose(STDOUT) // STDOUT doesn't exists...). Maybe, php is suppose to guess that using the Content-Length (bug?).

Perhaps it is apache which is waiting for the end of the process or the closing of the standard process output.

Finally, I think this become critical in AJAX aplications.

Thx
  J.A.

Reproduce code:
---------------
<? // hello.php
if (isset($_GET["a"])==false){
  ignore_user_abort(true);
  $msg="hello";
  header("Content-Length: ".strlen($msg));
  if (isset($_GET["close"])){ 
     header("Cache-Control: no-cache, must-revalidate");
     header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
     header("Connection: close");
  }
  echo $msg;
  flush();
  sleep(20);
}
else{
  echo "world!";
}
?>


Expected result:
----------------
just call the script twice:
hello.php 
=> hello
hello.php?a
=> world!
immediately

Actual result:
--------------
just call the script twice:
hello.php 
=> hello
hello.php?a
=> world!
after 20 seconds.