any idea why db.php builds a list of two identical server entries?

I discovered db.php was trying to “ping” the mysql server via fsockopen and apparently this is done to determine which server is more responsive in the pool.

However there is only one server, it confusingly builds a list of two of the same so I’d rather eliminate the cause than the effect.

For now I removed the effect by doing this:

$servers = array_unique($servers);

after this part

$servers = array();
                        ksort($server_groups);
                        foreach ( $server_groups as $group ) {
                                if ( count($group) > 1 )
                                        shuffle($group);
                                $servers = array_merge($servers, $group);
                        }

But I’d like to hunt down what might be wrong in the db-settings or in db.php itself to make an exact duplicate entry? Anyone more familiar with it that can give some ideas before I waste a couple hours on it?