Decreasing number of queries with drupal_lookup_path patch

Hello.

Now our team works on the project that is built on Drupal 5.3 with many modules plugged in and has a lot of content.
A lot of functionality is already implemented and now I'm researching performance problem.

Number of queries is a real problem.

I implemented some caching for several modules but number of queries still to high.

I'm using devel module for researching.

I found that drupal_lookup_path executed very often so I wrote some enhancement for this Drupal core function.

Drupal code (in includes/path.inc):

    if ($action == 'alias') {
      if (isset($map[$path])) {
        return $map[$path];
      }
      $alias = db_result(db_query("SELECT dst FROM {url_alias} WHERE src = '%s'", $path));
      $map[$path] = $alias;
      return $alias;
    }

with my changes:

    // in the static variables definition part
    static $searched = array();

    if ($action == 'alias') {
      if (isset($map[$path])) return $map[$path];
      
      $last_symbol = substr($path, -1, 1);
      if ($last_symbol >= '0' && $last_symbol <= '9') {
        $path_mask = substr($path, 0, -1);
        if (!isset($searched[$path_mask])) {
          $searched[$path_mask] = true;
          $result = db_query("SELECT src, dst FROM {url_alias} WHERE src LIKE '%s_' LIMIT 10", substr($path, 0, -1));
          while ($row = db_fetch_object($result)) {
            $map[$row->src] = $row->dst;
          }
        }
        return isset($map[$path]) ? $map[$path] : false;
      }
      
      $alias = db_result(db_query("SELECT dst FROM {url_alias} WHERE src = '%s'", $path));
      $map[$path] = $alias;
      return $alias;
    }

And now research results:
Native Drupal code:

• 518 queries in 1278.11 milliseconds
• 518 queries in 1390.44 milliseconds
• 518 queries in 1282.59 milliseconds
• 518 queries in 1326.65 milliseconds
• 518 queries in 1295.69 milliseconds
• Average is 518 queries in 1314 milliseconds

With my "enhancement"

• 427 queries in 1387.08 milliseconds
• 427 queries in 1230.76 milliseconds
• 427 queries in 1224.74 milliseconds
• 427 queries in 1248.26 milliseconds
• 427 queries in 1241.46 milliseconds
• Average is 427 queries in 1266 milliseconds

So, as you can see number of queries decresed by 17.5%, but total execution time decreased by 3.65% because of LIKE query.