db_set_active() and node_save() not working as expected
Here is some help:


The general format for the $databases array is as follows:
 * @code
 * $databases['default']['default'] = $info_array;
 * $databases['default']['slave'][] = $info_array;
 * $databases['default']['slave'][] = $info_array;
 * $databases['extra']['default'] = $info_array;
 * @endcode
 *
 * In the above example, $info_array is an array of settings described above.
 * The first line sets a "default" database that has one master database
 * (the second level default).  The second and third lines create an array
 * of potential slave databases.  Drupal will select one at random for a given
 * request as needed.  The fourth line creates a new database with a name of
 * "extra".



Are you sure Drupal can connect to the second database? Check your login credential, put some dummy table and do a db_query to verify they exist only in the second one.