(mysql) mysql-cluster-api-definition

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 15.4.4.6 Defining SQL and Other API Nodes
 .........................................
 
 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
 synonomous; you can, for instance, list parameters for a MySQL server
 acting as an SQL node in an `[API]' section.
 
    * `Id'
 
      The `Id' value is used to identify the node in all cluster
      internal messages. It must be an integer in the range 1 to 63
      inclusive, and must be unique among all node IDs within the
      cluster.
 
    * `ExecuteOnComputer'
 
      This refers to the `Id' set for one of the computers (hosts)
      defined in a `[COMPUTER]' section of the configuration file.
 
    * `HostName'
 
      Specifying this parameter defines the hostname of the computer on
      which the SQL node (API node) is to reside. To specify a hostname
      other than `localhost', either this parameter or
      `ExecuteOnComputer' is required.
 
    * `ArbitrationRank'
 
      This parameter defines which nodes can act as arbitrators.  Both
      MGM nodes and SQL nodes can be arbitrators. A value of 0 means
      that the given node is never used as an arbitrator, a value of 1
      gives the node high priority as an arbitrator, and a value of 2
      gives it low priority. A normal configuration uses the management
      server as arbitrator, setting its `ArbitrationRank' to 1 (the
      default) and those for all SQL nodes to 0.
 
    * `ArbitrationDelay'
 
      Setting this parameter to any other value than 0 (the default)
      means that responses by the arbitrator to arbitration requests
      will be delayed by the stated number of milliseconds. It is
      usually not necessary to change this value.
 
    * `BatchByteSize'
 
      For queries that are translated into full table scans or range
      scans on indexes, it is important for best performance to fetch
      records in properly sized batches. It is possible to set the
      proper size both in terms of number of records (`BatchSize') and
      in terms of bytes (`BatchByteSize'). The actual batch size is
      limited by both parameters.
 
      The speed at which queries are performed can vary by more than 40%
      depending upon how this parameter is set. In future releases,
      MySQL Server will make educated guesses on how to set parameters
      relating to batch size, based on the query type.
 
      This parameter is measured in bytes and by default is equal to
      32KB.
 
    * `BatchSize'
 
      This parameter is measured in number of records and is by default
      set to 64. The maximum size is 992.
 
    * `MaxScanBatchSize'
 
      The batch size is the size of each batch sent from each data node.
      Most scans are performed in parallel to protect the MySQL Server
      from receiving too much data from many nodes in parallel; this
      parameter sets a limit to the total batch size over all nodes.
 
      The default value of this parameter is set to 256KB. Its maximum
      size is 16MB.
 
 You can obtain some information from a MySQL server running as a
 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        | 192.168.0.112 |
      | Ndb_config_from_port        | 1186          |
      | Ndb_number_of_storage_nodes | 4             |
      +-----------------------------+---------------+
      4 rows in set (0.02 sec)
 
 For information about these Cluster system status variables, see 
 server-status-variables.
 

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