Oracle 5.0 Reference Manual page 1604

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
Effective Version
MySQL 5.0.0
Restart Type: N
This parameter is measured in number of records and is by default set to 64. The maximum size is
992.
•
MaxScanBatchSize
Effective Version
MySQL 5.0.0
Restart Type: N
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
in the client, as shown here:
STATUS mysql
mysql> SHOW STATUS LIKE 'ndb%';
+-----------------------------+---------------+
| Variable_name
+-----------------------------+---------------+
| Ndb_cluster_node_id
| Ndb_config_from_host
| Ndb_config_from_port
| Ndb_number_of_storage_nodes | 4
+-----------------------------+---------------+
4 rows in set (0.02 sec)
For information about these Cluster system status variables, see
Variables".
Note
To add new SQL or API nodes to the configuration of a running MySQL Cluster,
it is necessary to perform a rolling restart of all cluster nodes after adding new
[mysqld]
more than one management server). This must be done before the new SQL or
API nodes can connect to the cluster.
MySQL Cluster Configuration Files
Type/Units
records
Type/Units
bytes
| Value |
| 5 |
| 192.168.0.112 |
| 1186 |
|
or sections to the
[api]
1584
Default
64
Default
256K
Section 5.1.6, "Server Status
file (or files, if you are using
config.ini
Range/Values
1 - 992
Range/Values
32K - 16M
SHOW