25.4.3.7 Defining SQL and Other API Nodes in an NDB Cluster (original) (raw)

25.4.3.7 Defining SQL and Other API Nodes in an NDB Cluster

The [mysqld] and [api] sections in the config.ini file define the behavior of the MySQL servers (SQL nodes) and other applications (API nodes) used to access cluster data. None of the parameters shown is required. If no computer or host name is provided, any host can use this SQL or API node.

Generally speaking, a [mysqld] section is used to indicate a MySQL server providing an SQL interface to the cluster, and an [api] section is used for applications other than mysqld processes accessing cluster data, but the two designations are actually synonymous; you can, for instance, list parameters for a MySQL server acting as an SQL node in an [api] section.

HeartbeatThreadPriority = policy[, priority]  
policy:  
  {FIFO | RR}

When setting this parameter, you must specify a policy. This is one of FIFO (first in, first in) orRR (round robin). This followed optionally by the priority (an integer).

API Node Debugging Parameters. You can use the ApiVerbose configuration parameter to enable debugging output from a given API node. This parameter takes an integer value. 0 is the default, and disables such debugging; 1 enables debugging output to the cluster log; 2 adds DBDICT debugging output as well. (Bug #20638450) See alsoDUMP 1229.

You can also obtain information from a MySQL server running as an NDB Cluster SQL node using SHOW STATUS in the mysql client, as shown here:

mysql> SHOW STATUS LIKE 'ndb%';
+-----------------------------+----------------+
| Variable_name               | Value          |
+-----------------------------+----------------+
| Ndb_cluster_node_id         | 5              |
| Ndb_config_from_host        | 198.51.100.112 |
| Ndb_config_from_port        | 1186           |
| Ndb_number_of_storage_nodes | 4              |
+-----------------------------+----------------+
4 rows in set (0.02 sec)

For information about the status variables appearing in the output from this statement, seeSection 25.4.3.9.3, “NDB Cluster Status Variables”.

Note

To add new SQL or API nodes to the configuration of a running NDB Cluster, it is necessary to perform a rolling restart of all cluster nodes after adding new [mysqld] or [api] sections to theconfig.ini file (or files, if you are using more than one management server). This must be done before the new SQL or API nodes can connect to the cluster.

It is not necessary to perform any restart of the cluster if new SQL or API nodes can employ previously unused API slots in the cluster configuration to connect to the cluster.

Restart types. Information about the restart types used by the parameter descriptions in this section is shown in the following table:

Table 25.18 NDB Cluster restart types

Symbol Restart Type Description
N Node The parameter can be updated using a rolling restart (seeSection 25.6.5, “Performing a Rolling Restart of an NDB Cluster”)
S System All cluster nodes must be shut down completely, then restarted, to effect a change in this parameter
I Initial Data nodes must be restarted using the--initial option