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 | Description |
|---|---|---|
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. |
remote_address | string | Name or IP address of the remote host |
bytes_sent | integer | Number of bytes sent using this connection |
bytes_received | Number of bytes received using this connection | |
connect_count | Number of times connection established on this transporter | |
overloaded | 1 if this transporter is currently overloaded, otherwise 0 | |
overload_count | Number of times this transporter has entered overload state since connecting | |
slowdown | 1 if this transporter is in scan slowdown state, otherwise 0 | |
slowdown_count | Number of times this transporter has entered scan slowdown state since connecting |
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.
The remote_address is the host name or
address for the node whose ID is shown in the
remote_node_id column. The
bytes_sent from this node and
bytes_received by this node are the numbers,
respectively, of bytes sent and received by the node using this
connection since it was established. For nodes whose status is
CONNECTING or
DISCONNECTED, these columns always display
0.
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_send and
bytes_received counters are also reset on
connection, and so retain their values following disconnection
(until the next connection resets them).
Assume you have a 5-node cluster consisting 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 (5.6.35-ndb-7.4.15, Nodegroup: 0, *)
id=2 @10.100.10.2 (5.6.35-ndb-7.4.15, Nodegroup: 0)
[ndb_mgmd(MGM)] 1 node(s)
id=10 @10.100.10.10 (5.6.35-ndb-7.4.15)
[mysqld(API)] 2 node(s)
id=20 @10.100.10.20 (5.6.35-ndb-7.4.15)
id=21 @10.100.10.21 (5.6.35-ndb-7.4.15)
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)