MD5 vs. preg_replace_callback for PDOStament::bindParam() usage in zend-db

test_bench.php

<?php
// Testing md5 vs. preg_replace_callback()
$execPreg = 0;
$execMd5 = 0;

for ($i=0; $i<100000; $i++) {
  $name = randomName(10);

  $start = microtime(true);
  $result = preg_replace_callback(
      '/([^a-zA-Z0-9_])/',
      function ($matches) {
          return '_' . ord($matches[0]) . '_';
       },
       $name
  );
  $execPreg += microtime(true) - $start;

  $start = microtime(true);
  $result = md5($name);
  $execMd5 += microtime(true) - $start;
}

printf ("Exec time (preg): %f.4\n", $execPreg);
printf ("Exec time (md5) : %f.4\n", $execMd5);

function randomName($size) {
  $alphabet = 'abcdefghijklmnopqrstuvwxyz0123456789_$-%&£';
  $tot = strlen($alphabet);
  $result = '';
  for ($i=0; $i<$size; $i++) {
    $result .= $alphabet[random_int(0, $tot-1)];
  }
  return $result;
}