MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
The ndb_mgm management client process is actually not needed to run the cluster. Its value lies in providing a set of commands for checking the cluster's status, starting backups, and performing other administrative functions. The management client accesses the management server using a C API. Advanced users can also employ this API for programming dedicated management processes to perform tasks similar to those performed by ndb_mgm.
To start the management client, it is necessary to supply the host name and port number of the management server:
$> ndb_mgm [host_name [port_num]]
For example:
$> ndb_mgm ndb_mgmd.mysql.com 1186
The default host name and port number are
localhost and 1186, respectively.
Options that can be used with ndb_mgm are shown in the following table. Additional descriptions follow the table.
Table 21.25 Command-line options used with the program ndb_mgm
| Format | Description | Added, Deprecated, or Removed |
|---|---|---|
| Directory containing character sets | (Supported in all NDB releases based on MySQL 5.7) |
|
| Number of seconds to wait between attempts to contact management server | (Supported in all NDB releases based on MySQL 5.7) |
|
| Same as --ndb-connectstring | (Supported in all NDB releases based on MySQL 5.7) |
|
| Write core file on error; used in debugging | (Supported in all NDB releases based on MySQL 5.7) |
|
| Read given file after global files are read | (Supported in all NDB releases based on MySQL 5.7) |
|
| Read default options from given file only | (Supported in all NDB releases based on MySQL 5.7) |
|
| Also read groups with concat(group, suffix) | (Supported in all NDB releases based on MySQL 5.7) |
|
| Execute command and exit | (Supported in all NDB releases based on MySQL 5.7) |
|
| Display help text and exit | (Supported in all NDB releases based on MySQL 5.7) |
|
| Read given path from login file | (Supported in all NDB releases based on MySQL 5.7) |
|
| Set connect string for connecting to ndb_mgmd. Syntax: "[nodeid=id;][host=]hostname[:port]". Overrides entries in NDB_CONNECTSTRING and my.cnf | (Supported in all NDB releases based on MySQL 5.7) |
|
| Same as --ndb-connectstring | (Supported in all NDB releases based on MySQL 5.7) |
|
| Set node ID for this node, overriding any ID set by --ndb-connectstring | (Supported in all NDB releases based on MySQL 5.7) |
|
| Enable optimizations for selection of nodes for transactions. Enabled by default; use --skip-ndb-optimized-node-selection to disable | (Supported in all NDB releases based on MySQL 5.7) |
|
| Do not read default options from any option file other than login file | (Supported in all NDB releases based on MySQL 5.7) |
|
| Print program argument list and exit | (Supported in all NDB releases based on MySQL 5.7) |
|
| Set number of times to retry connection before giving up; synonym for --connect-retries | (Supported in all NDB releases based on MySQL 5.7) |
|
| Display help text and exit; same as --help | (Supported in all NDB releases based on MySQL 5.7) |
|
| Display version information and exit | (Supported in all NDB releases based on MySQL 5.7) |
| Command-Line Format | --character-sets-dir=path |
|---|
Directory containing character sets.
| Command-Line Format | --connect-retries=# |
|---|---|
| Type | Numeric |
| Default Value | 3 |
| Minimum Value | 0 |
| Maximum Value | 4294967295 |
This option specifies the number of times following the
first attempt to retry a connection before giving up (the
client always tries the connection at least once). The
length of time to wait per attempt is set using
--connect-retry-delay.
This option is synonymous with the
--try-reconnect option,
which is now deprecated.
| Command-Line Format | --connect-retry-delay=# |
|---|---|
| Type | Integer |
| Default Value | 5 |
| Minimum Value | 0 |
| Maximum Value | 5 |
Number of seconds to wait between attempts to contact management server.
| Command-Line Format | --connect-string=connection_string |
|---|---|
| Type | String |
| Default Value | [none] |
Same as --ndb-connectstring.
| Command-Line Format | --core-file |
|---|
Write core file on error; used in debugging.
| Command-Line Format | --defaults-extra-file=path |
|---|---|
| Type | String |
| Default Value | [none] |
Read given file after global files are read.
| Command-Line Format | --defaults-file=path |
|---|---|
| Type | String |
| Default Value | [none] |
Read default options from given file only.
| Command-Line Format | --defaults-group-suffix=string |
|---|---|
| Type | String |
| Default Value | [none] |
Also read groups with concat(group, suffix).
| Command-Line Format | --execute=command |
|---|
This option can be used to send a command to the NDB Cluster
management client from the system shell. For example, either
of the following is equivalent to executing
SHOW in the management
client:
$>ndb_mgm -e "SHOW"$>ndb_mgm --execute="SHOW"
This is analogous to how the
--execute or
-e option works with the
mysql command-line client. See
Section 4.2.2.1, “Using Options on the Command Line”.
If the management client command to be passed using this option contains any space characters, then the command must be enclosed in quotation marks. Either single or double quotation marks may be used. If the management client command contains no space characters, the quotation marks are optional.
| Command-Line Format | --help |
|---|
Display help text and exit.
| Command-Line Format | --login-path=path |
|---|---|
| Type | String |
| Default Value | [none] |
Read given path from login file.
| Command-Line Format | --ndb-connectstring=connection_string |
|---|---|
| Type | String |
| Default Value | [none] |
Set connect string for connecting to
ndb_mgmd. Syntax:
[nodeid=][id;host=]hostname:].
Overrides entries in portNDB_CONNECTSTRING
and my.cnf.
| Command-Line Format | --ndb-mgmd-host=connection_string |
|---|---|
| Type | String |
| Default Value | [none] |
Same as --ndb-connectstring.
| Command-Line Format | --ndb-nodeid=# |
|---|---|
| Type | Integer |
| Default Value | [none] |
Set node ID for this node, overriding any ID set by
--ndb-connectstring.
--ndb-optimized-node-selection
| Command-Line Format | --ndb-optimized-node-selection |
|---|
Enable optimizations for selection of nodes for
transactions. Enabled by default; use
--skip-ndb-optimized-node-selection to
disable.
| Command-Line Format | --no-defaults |
|---|
Do not read default options from any option file other than login file.
| Command-Line Format | --print-defaults |
|---|
Print program argument list and exit.
| Command-Line Format | --try-reconnect=# |
|---|---|
| Deprecated | Yes |
| Type (≥ 5.7.10-ndb-7.5.0) | Numeric |
| Type | Integer |
| Default Value (≥ 5.7.10-ndb-7.5.0) | 12 |
| Default Value | 3 |
| Minimum Value | 0 |
| Maximum Value | 4294967295 |
If the connection to the management server is broken, the
node tries to reconnect to it every 5 seconds until it
succeeds. By using this option, it is possible to limit the
number of attempts to number
before giving up and reporting an error instead.
This option is deprecated and subject to removal in a future
release. Use
--connect-retries, instead.
| Command-Line Format | --usage |
|---|
Display help text and exit; same as
--help.
| Command-Line Format | --version |
|---|
Display version information and exit.
Additional information about using ndb_mgm can be found in Section 21.6.1, “Commands in the NDB Cluster Management Client”.