PDOException: SQLSTATE[42000] [1044] Access denied for user 'lacare_d7'@'localhost' to database.

I got the following error when i cloned my database to a new one with a different name. I tried to reconnect my application tier to the new renamed database, it gave me the error as below.

"PDOException: SQLSTATE[42000] [1044] Access denied for user 'lacare_d7'@'localhost' to database 'lacare_d7_staging' in lock_may_be_available() (line 167 of /var/www/staging/html/includes/lock.inc)."

Since I have root account for this mysql server, I log in and ran successfully the following command:

mysql>  GRANT ALL PRIVILEGES ON lac2014_staging TO 'lac2014'@'localhost';
Query OK, 0 rows affected (0.00 sec)

It doesn't make any difference. Then I checked the file mentioned on the error message:
/var/www/staging/html/includes/lock.inc

got the 167th line as below:

155 /**
    156  * Check if lock acquired by a different process may be available.
    157  *
    158  * If an existing lock has expired, it is removed.
    159  *
    160  * @param $name
    161  *   The name of the lock.
    162  *
    163  * @return
    164  *   TRUE if there is no lock or it was removed, FALSE otherwise.
    165  */
    166 function lock_may_be_available($name) {
    167   $lock = db_query('SELECT expire, value FROM {semaphore} WHERE name = :name', array(':name' => $name))->fetchAssoc();
    168   if (!$lock) {
    169     return TRUE;
    170   }
    171   $expire = (float) $lock['expire'];
    172   $now = microtime(TRUE);
    173   if ($now > $expire) {
    174     // We check two conditions to prevent a race condition where another
    175     // request acquired the lock and set a new expire time. We add a small
    176     // number to $expire to avoid errors with float to string conversion.
    177     return (bool) db_delete('semaphore')
    178       ->condition('name', $name)
    179       ->condition('value', $lock['value'])
    180       ->condition('expire', 0.0001 + $expire, '<=')
    181       ->execute();
    182   }
    183   return FALSE;

Select allOpen in new window

Please help me with this hard issue.