id=1 @10.100.10.1 (8.0.26-ndb-8.0.26, Nodegroup: 0, *) id=2 @10.100.10.2 (8.0.26-ndb-8.0.26, Nodegroup: 0) [ndb_mgmd(MGM)] 1 node(s) id=10 @10.100.10.10 (8.0.26-ndb-8.0.26) [mysqld(API)] 2 node(s) id=20 @10.100.10.20 (8.0.26-ndb-8.0.26) id=21 @10.100.10.21 (8.0.26-ndb-8.0.26) 

There are 10 rows in the transporters  table—5 for the first data node, and 5 for the second—assuming that all data nodes are running, as shown here: 

mysql> SELECT node_id, remote_node_id, status -> FROM ndbinfo.transporters; +---------+----------------+---------------+ | node_id | remote_node_id | status | +---------+----------------+---------------+ | 1 | 1 | DISCONNECTED | | 1 | 2 | CONNECTED | | 1 | 10 | CONNECTED | | 1 | 20 | CONNECTED | | 1 | 21 | CONNECTED | | 2 | 1 | CONNECTED | | 2 | 2 | DISCONNECTED | | 2 | 10 | CONNECTED | | 2 | 20 | CONNECTED | | 2 | 21 | CONNECTED | +---------+----------------+---------------+ 10 rows in set (0.04 sec) 

If you shut down one of the data nodes in this cluster using the command 2 STOP  in the ndb_mgm  client, then repeat the previous query (again using the mysql  client), this table now shows only 5 rows—1 row for each connection from the remaining management node to another node, including both itself and the data node that is currently offline—and displays CONNECTING  for the status of each remaining connection to the data node that is currently offline, as shown here: 

mysql> SELECT node_id, remote_node_id, status -> FROM ndbinfo.transporters; +---------+----------------+---------------+ | node_id | remote_node_id | status | +---------+----------------+---------------+ | 1 | 1 | DISCONNECTED | | 1 | 2 | CONNECTING | | 1 | 10 | CONNECTED | | 1 | 20 | CONNECTED | | 1 | 21 | CONNECTED | +---------+----------------+---------------+ 5 rows in set (0.02 sec) 

The connect_count , overloaded , overload_count , slowdown , and slowdown_count  counters are reset on connection, and retain their values after the remote node disconnects. The bytes_sent and bytes_received  counters are also reset on connection, and so retain their values following disconnection (until the next connection resets them). 

The overload  state referred to by the overloaded  and overload_count  columns occurs when this transporter’s send buffer contains more than OVerloadLimit  bytes (default is 80% of SendBufferMemory , that is, 0.8 * 2097152 = 1677721 bytes). When a given transporter is in a state of overload, any new transaction that tries to use this transporter fails with Error 1218 ( Send Buffers overloaded in NDB kernel ). This affects both scans and primary key operations. 

The slowdown  state referenced by the slowdown  and slowdown_count  columns of this table occurs when the transporter’s send buffer contains more than 60% of the overload limit (equal to 0.6 * 2097152 = 

