If a custom field name changed, custom_field_get_id_from_name() keeps asking the database for an id over and over again (e. g. for every change of the field in the bug history to decide if it should be displayed).

Patch:

--- mantisbt-1.2.12\core\custom_field_api.php 2012-12-06 16:00:27.000000000 +0100
+++ mantisbt-1.2.12-new\core\custom_field_api.php 2012-12-06 16:19:09.000000000 +0100
@@ -648,12 +648,13 @@
$c_field_name = $p_field_name . '%';
}

$t_result = db_query_bound( $query, array( $c_field_name ) );

if( db_num_rows( $t_result ) == 0 ) {

• $g_cache_name_to_id_map[$p_field_name] = false;
  return false;
  }

  $row = db_fetch_array( $t_result );
  $g_cache_name_to_id_map[$p_field_name] = $row['id'];