16.4.4.7. MySQL Cluster TCP/IP Connections
TCP/IP is the default transport mechanism for establishing
connections in MySQL Cluster. It is normally not necessary to
define connections because Cluster automatically set ups a
connection between each of the data nodes, between each data
node and all MySQL server nodes, and between each data node
and the management server. (For one exception to this rule,
see Section 16.4.4.8, “MySQL Cluster TCP/IP Connections Using Direct Connections”.)
[TCP] sections in the
config.ini file explicitly define TCP/IP
connections between nodes in the cluster.
It is only necessary to define a connection to override the
default connection parameters. In that case, it is necessary
to define at least NodeId1,
NodeId2, and the parameters to change.
It is also possible to change the default values for these
parameters by setting them in the [TCP
DEFAULT] section.
-
NodeId1, NodeId2
To identify a connection between two nodes it is necessary
to provide their node IDs in the [TCP]
section of the configuration file. These are the same
unique Id values for each of these
nodes as described in
Section 16.4.4.6, “Defining the SQL Nodes in a MySQL Cluster”.
-
SendBufferMemory
TCP transporters use a buffer to store all messages before
performing the send call to the operating system. When
this buffer reaches 64KB its contents are sent; these are
also sent when a round of messages have been executed. To
handle temporary overload situations it is also possible
to define a bigger send buffer. The default size of the
send buffer is 256KB.
-
SendSignalId
To be able to retrace a distributed message diagram it is
necessary to identify each message. When this parameter is
set to Y, message IDs are transported
over the network. This feature is disabled by default.
-
Checksum
This parameter is a boolean parameter (enabled by setting
it to Y or 1,
disabled by setting it to N or
0). It is disabled by default. When it
is enabled, checksums for all messages are calculated
before they placed in the send buffer. This feature
ensures that messages are not corrupted while waiting in
the send buffer, or by the transport mechanism.
-
PortNumber
(OBSOLETE)
This formerly specified the port number to be used for
listening for connections from other nodes. This parameter
should no longer be used.
-
ReceiveBufferMemory
Specifies the size of the buffer used when receiving data
from the TCP/IP socket. There is seldom any need to change
this parameter from its default value of 64KB, except
possibly to save memory.
