Drupal 7: Displaying external SQL-table as paginated list
the squiggly brackets are used for escaping table names in drupal. For cases where you have multiple sites in one database.

I'm guessing that you have a db prefix set up for all of your Drupal tables to be drupal_

You can set this on a db connection before $result = $query-&gt;execute(); using the setprefix method

Something like 

 $query-&gt;setprefix(array(
     'default'   =&gt; 'drupal_',
     'perf_users'     =&gt; ''));


untested code

may do it. However you are more likely to want to change your settings.php file and set table prefixs in there