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17.5.9 MySQL Cluster Security Issues »
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17.5.8.10. The ndbinfo transporters Table

This table contains information about NDB transporters.

The following table provides information about the columns in the transporters table. For each column, the table shows the name, data type, and a brief description. Additional information can be found in the notes following the table.

Column Name Type Remarks
node_id integer This data node's unique node ID in the cluster.
remote_node_id integer The remote data node's node ID.
status string Status of the connection.

For each running data node in the cluster, the transporters table displays a row showing the status of each of that node's connections with all nodes in the cluster, including itself. This information is shown in the table's status column, which can have any one of the following values: CONNECTING, CONNECTED, DISCONNECTING, or DISCONNECTED.

Connections to API and management nodes which are configured but not currently connected to the cluster are shown with status DISCONNECTED. Rows where the node_id is that of a data nodes which is not currently connected are not shown in this table. (This is similar omission of disconnected nodes in the ndbinfo.nodes table — see Section 17.5.8.7, “The ndbinfo nodes Table”, for more information).

Assume you have a 5-node cluster conisting of 2 data nodes, 2 SQL nodes, and 1 management node, as shown in the output of the SHOW command in the ndb_mgm client: 

ndb_mgm> SHOW
Connected to Management Server at: localhost:1186
Cluster Configuration
---------------------
[ndbd(NDB)]     2 node(s)
id=1    @10.100.10.1  (mysql-5.1.41 ndb-7.1.1, Nodegroup: 0, Master)
id=2    @10.100.10.2  (mysql-5.1.41 ndb-7.1.1, Nodegroup: 0)

[ndb_mgmd(MGM)] 1 node(s)
id=10   @10.100.10.10  (mysql-5.1.41 ndb-7.1.1)

[mysqld(API)]   2 node(s)
id=20   @10.100.10.20  (mysql-5.1.41 ndb-7.1.1)
id=21   @10.100.10.21  (mysql-5.1.41 ndb-7.1.1)

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 * FROM transporters;
+---------+----------------+---------------+
| node_id | remote_node_id | status        |
+---------+----------------+---------------+
|       1 |              1 | CONNECTED     |
|       1 |              2 | CONNECTED     |
|       1 |             10 | CONNECTED     |
|       1 |             20 | CONNECTED     |
|       1 |             21 | CONNECTED     |
|       2 |              1 | CONNECTED     |
|       2 |              2 | CONNECTED     |
|       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 ndb_mgm client STOP command, then repeat the query, this table now shows only 5 rows — 1 row for each connection from the remaining data node to another node, including both itself and the data node that is currently offline, as shown here: 

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