674,675c674
<       $try = $limit * 4;
<       $sql = "SELECT distinct meta_key
---
>       $sql = "SELECT meta_key
676a676,678
>               GROUP BY meta_key
>               HAVING meta_key NOT LIKE %s
>               ORDER BY meta_key
678c680
<       $keys = $wpdb->get_col( $wpdb->prepare( $sql, $try ) );
---
>       $keys = $wpdb->get_col( $wpdb->prepare( $sql, $wpdb->esc_like( '_' ) . '%', $limit ) );
681,688d682
<               foreach($keys as $index => $key) {
<                       if ($key[0] == '_') {
<                               unset($keys[$index]);
<                       }
<               }
<               if (count($keys) > $limit) {
<                       $keys = array_slice($keys, 0, $limit);
<               }