only solve this with a cookie

<?php
  // GETTING THE TITLES INTO THE ARRAY
$sql = 'SELECT id,content FROM products';
$res = mysql_query($sql) or die("FAIL: $sql <br/> " . mysql_error());
while ($row = mysql_fetch_assoc($res))
{
    $string[]=$row;
}

// SHOWING THE ARRAY OF TITLES
//print_r($string);

// COMPARISONS USING SIMILAR_TEXT() BUT SEE THE NOTES HERE BEFORE YOU USE IT!
// http://php.net/manual/en/function.similar-text.php#109507
// COMPARISONS USING SIMILAR_TEXT



foreach ($string as $x)
{
    //echo PHP_EOL . "TESTING <b>$x</b> WITH SIMILAR_TEXT()";

    // COMPARE TO THE OTHER STRINGS
    foreach ($string as $y)
    {   
        $ss = 
        similar_text(
        $x['content'], 
        $y['content'], 
        $sp);
        if (number_format($sp,0)>=75 && number_format($sp,0)<100){
          $sql="insert into similar(orig,sim,per) values('{$x['id']}','{$y['id']}',".number_format($sp,0).");";
          echo '<br>'.$sql;
        }
    }
}
?>

this program takes hours (almost a day to run) because I am comparing many large product descriptions

I read
http://php.net/manual/en/function.setcookie.php
and other php.net pages and do not understand how I can implement cookie for this script
and how I can resume the foreach loop

I am not looking for a cpu answer or to change the code or use another database or scripting language or to write to a database or write to a file

want to put a cookie so I know $x['id']
so if browser crashes I can continue comparison