Description:
------------
I am testing the following code that pushes a file to the browser 
(Linux + Apache 1.3 + PHP 4.3.10 but tested also under several other configs)

!!!!!!
Try it with a BIG test1.zip (e.g. 100M in size)

Try it with wget http://server/test.php or a browser but the result is more accurate when using wget since in browsers could work if you already had a succesfull download of a smaller file.
!!!!!!

What i discovered is that if i keep the 2 session initialisation functions
the script will work ONLY if the allocated memory in php.ini is greater than the size
of the tested file. If i remove the session functions the script works fine
even if the test1.zip file is very big (hundreds of Megs)

Reproduce code:
---------------
<?php
session_save_path('/tmp');
session_start();
$sFileName = 'test1.zip';
$sFileDir = '/var/www/html/';
header("Content-Type: application/octet-stream");
header("Content-Disposition: attachment;filename=\"" . $sFileName . "\"");
header("Content-Length: " . filesize($sFileDir . $sFileName));
header('Pragma: cache');
header('Cache-Control: public, must-revalidate, max-age=0');
header('Connection: close');
header('Expires: ' . date('r', time()+60*60));
header('Last-Modified: ' . date('r', time()));
$oFp = fopen($sFileDir . $sFileName, "rb");
$iReadBufferSize = 512;
while (!feof($oFp)) {
        echo fread ($oFp, $iReadBufferSize);
}
fclose ($oFp);
exit;
?>

Expected result:
----------------
The file should dowload via a browser or via wget

Actual result:
--------------
tail from apache error_log:

Allowed memory size of 12582912 bytes exhausted (tried to allocate 10240 bytes)