Session in PHP

i have two files in php both have the same code and the file is
<?php
session_start();

$con = mysql_connect("l","root",""); // here localhost and password will be filled accordingly
if (!$con)
{
die('Connection failure: ' . mysql_error());
}

mysql_select_db("student",$con);

$fetch=mysql_query("SELECT * from student1") or die(mysql_error());
$row = mysql_fetch_array($fetch) or die(mysql_error());

sleep(10);

echo "Name: ".$row[0]."</br>";
echo " Age: ".$row[1]."</br>";
echo " Address: ".$row[2];
mysql_close($con);
?>
Now i have another file which has the same code as above except there is no sleep function used in it . Now when i run the file which is wothout sleep it displyas results in seconds however the file with sleep function takes it time.

Now the problem is if i load the file woth sleep function first then its delayed nature is reflected in another file which is without sleep() i.e now the file without sleep is taking longer time to open.

plz explain all this and possible solution to this problem
the other file is

<?php
session_start();

$con = mysql_connect("localhost","root","instablogs");
if (!$con)
{
die('Connection failure: ' . mysql_error());
}

mysql_select_db("student",$con);

$fetch=mysql_query("SELECT * from student1") or die(mysql_error());
$row = mysql_fetch_array($fetch) or die(mysql_error());

echo "Name: ".$row[0]."</br>";
echo " Age: ".$row[1]."</br>";
echo " Address: ".$row[2]."</br>";

mysql_close($con);

?>