This table contains information about NDB Cluster node
processes; each node is represented by the row in the table.
Only nodes that are connected to the cluster are shown in this
table. You can obtain information about nodes that are
configured but not connected to the cluster from the
nodes
and
config_nodes
tables.
The processes
table contains the following
columns:
node_id
The node's unique node ID in the cluster
node_type
Type of node (management, data, or API node; see text)
node_version
Version of the
NDB
software program running on this node.process_id
This node's process ID
angel_process_id
Process ID of this node's angel process
process_name
Name of the executable
service_URI
Service URI of this node (see text)
Notes
node_id
is the ID assigned to this node in
the cluster.
The node_type
column displays one of the
following three values:
MGM
: Management node.NDB
: Data node.API
: API or SQL node.
For an executable shipped with the NDB Cluster distribution,
node_version
shows the software Cluster
version string, such as
8.4.0-ndb-8.4.0
.
process_id
is the node executable's
process ID as shown by the host operating system using a process
display application such as top on Linux, or
the Task Manager on Windows platforms.
angel_process_id
is the system process ID for
the node's angel process, which ensures that a data node or
SQL is automatically restarted in cases of failures. For
management nodes and API nodes other than SQL nodes, the value
of this column is NULL
.
The process_name
column shows the name of the
running executable. For management nodes, this is
ndb_mgmd
. For data nodes, this is
ndbd
(single-threaded) or
ndbmtd
(multithreaded). For SQL nodes, this
is mysqld
. For other types of API nodes, it
is the name of the executable program connected to the cluster;
NDB API applications can set a custom value for this using
Ndb_cluster_connection::set_name()
.
service_URI
shows the service network
address. For management nodes and data nodes, the scheme used is
ndb://
. For SQL nodes, this is
mysql://
. By default, API nodes other than
SQL nodes use ndb://
for the scheme; NDB API
applications can set this to a custom value using
Ndb_cluster_connection::set_service_uri()
.
regardless of the node type, the scheme is followed by the IP
address used by the NDB transporter for the node in question.
For management nodes and SQL nodes, this address includes the
port number (usually 1186 for management nodes and 3306 for SQL
nodes). If the SQL node was started with the
bind_address
system variable
set, this address is used instead of the transporter address,
unless the bind address is set to *
,
0.0.0.0
, or ::
.
Additional path information may be included in the
service_URI
value for an SQL node reflecting
various configuration options. For example,
mysql://198.51.100.3/tmp/mysql.sock
indicates
that the SQL node was started with the
skip_networking
system variable
enabled, and
mysql://198.51.100.3:3306/?server-id=1
shows
that replication is enabled for this SQL node.