MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0
ndb_top displays running information in the terminal about CPU usage by NDB threads on an NDB Cluster data node. Each thread is represented by two rows in the output, the first showing system statistics, the second showing the measured statistics for the thread.
ndb_top is available beginning with MySQL NDB Cluster 7.6.3.
ndb_top [-hhostname
] [-tport
] [-uuser
] [-ppass
] [-nnode_id
]
ndb_top connects to a MySQL Server running as
an SQL node of the cluster. By default, it attempts to connect
to a mysqld running on
localhost
and port 3306, as the MySQL
root
user with no password specified. You can
override the default host and port using, respectively,
--host
(-h
) and
--port
(-t
). To
specify a MySQL user and password, use the
--user
(-u
) and
--passwd
(-p
)
options. This user must be able to read tables in the
ndbinfo
database
(ndb_top uses information from
ndbinfo.cpustat
and related
tables).
For more information about MySQL user accounts and passwords, see Section 6.2, “Access Control and Account Management”.
Output is available as plain text or an ASCII graph; you can
specify this using the --text
(-x
) and
--graph
(-g
)
options, respectively. These two display modes provide the same
information; they can be used concurrently. At least one display
mode must be in use.
Color display of the graph is supported and enabled by default
(--color
or -c
option). With color support enabled, the graph display shows OS
user time in blue, OS system time in green, and idle time as
blank. For measured load, blue is used for execution time,
yellow for send time, red for time spent in send buffer full
waits, and blank spaces for idle time. The percentage shown in
the graph display is the sum of percentages for all threads
which are not idle. Colors are not currently configurable; you
can use grayscale instead by using
--skip-color
.
The sorted view (--sort
,
-r
) is based on the maximum of the measured
load and the load reported by the OS. Display of these can be
enabled and disabled using the
--measured-load
(-m
) and
--os-load
(-o
)
options. Display of at least one of these loads must be enabled.
The program tries to obtain statistics from a data node having
the node ID given by the
--node-id
(-n
)
option; if unspecified, this is 1. ndb_top
cannot provide information about other types of nodes.
The view adjusts itself to the height and width of the terminal window; the minimum supported width is 76 characters.
Once started, ndb_top runs continuously until
forced to exit; you can quit the program using
Ctrl-C
. The display updates once per second;
to set a different delay interval, use
--sleep-time
(-s
).
ndb_top is available on macOS, Linux, and Solaris. It is not currently supported on Windows platforms.
The following table includes all options that are specific to the NDB Cluster program ndb_top. Additional descriptions follow the table.
Table 23.48 Command-line options for the ndb_top program
Format | Description | Added, Deprecated, or Removed |
---|---|---|
Show ASCII graphs in color; use --skip-colors to disable | (Supported in all MySQL 8.0 based releases) |
|
Display data using graphs; use --skip-graphs to disable | (Supported in all MySQL 8.0 based releases) |
|
Show program usage information | (Supported in all MySQL 8.0 based releases) |
|
Host name or IP address of MySQL Server to connect to | (Supported in all MySQL 8.0 based releases) |
|
Show measured load by thread | (Supported in all MySQL 8.0 based releases) |
|
Watch node having this node ID | (Supported in all MySQL 8.0 based releases) |
|
Show load measured by operating system | (Supported in all MySQL 8.0 based releases) |
|
Connect using this password | (Supported in all MySQL 8.0 based releases) |
|
|
Port number to use when connecting to MySQL Server | (Supported in all MySQL 8.0 based releases) |
Time to wait between display refreshes, in seconds | (Supported in all MySQL 8.0 based releases) |
|
Socket file to use for connection | (Supported in all MySQL 8.0 based releases) |
|
Sort threads by usage; use --skip-sort to disable | (Supported in all MySQL 8.0 based releases) |
|
|
Display data using text | (Supported in all MySQL 8.0 based releases) |
Connect as this MySQL user | (Supported in all MySQL 8.0 based releases) |
In NDB 7.6.6 and later, ndb_top also supports
the common NDB
program options
--defaults-file
,
--defaults-extra-file
,
--print-defaults
,
--no-defaults
, and
--defaults-group-suffix
. (Bug
#86614, Bug #26236298)
Command-Line Format | --color |
---|---|
Type | Boolean |
Default Value | TRUE |
Show ASCII graphs in color; use
--skip-colors
to disable.
Command-Line Format | --graph |
---|---|
Type | Boolean |
Default Value | TRUE |
Display data using graphs; use
--skip-graphs
to disable. This option or
--text
must be true; both
options may be true.
Command-Line Format | --help |
---|---|
Type | Boolean |
Default Value | TRUE |
Show program usage information.
Command-Line Format | --host[=name] |
---|---|
Type | String |
Default Value | localhost |
Host name or IP address of MySQL Server to connect to.
Command-Line Format | --measured-load |
---|---|
Type | Boolean |
Default Value | FALSE |
Show measured load by thread. This option or
--os-load
must be true; both
options may be true.
Command-Line Format | --node-id[=#] |
---|---|
Type | Integer |
Default Value | 1 |
Watch the data node having this node ID.
Command-Line Format | --os-load |
---|---|
Type | Boolean |
Default Value | TRUE |
Show load measured by operating system. This option or
--measured-load
must be
true; both options may be true.
Command-Line Format | --passwd[=password] |
---|---|
Type | Boolean |
Default Value | NULL |
Connect using this password.
This option is deprecated in NDB 7.6.4. It is removed in NDB
7.6.6, where it is replaced by the
--password
option. (Bug
#26907833)
Command-Line Format | --password[=password] |
---|---|
Type | Boolean |
Default Value | NULL |
Connect using this password.
This option was added in NDB 7.6.6 as a replacement for the
--passwd
option used
previously. (Bug #26907833)
--port[
=#]
,
-t
(NDB 7.6.6 and later:
-P
)
Command-Line Format | --port[=#] |
---|---|
Type | Integer |
Default Value | 3306 |
Port number to use when connecting to MySQL Server.
Beginning with NDB 7.6.6, the short form for this option is
-P
, and -t
is repurposed
as the short form for the
--text
option. (Bug
#26907833)
Command-Line Format | --sleep-time[=seconds] |
---|---|
Type | Integer |
Default Value | 1 |
Time to wait between display refreshes, in seconds.
Command-Line Format | --socket |
---|---|
Type | Path name |
Default Value | [none] |
Use the specified socket file for the connection.
Added in NDB 7.6.6. (Bug #86614, Bug #26236298)
Command-Line Format | --sort |
---|---|
Type | Boolean |
Default Value | TRUE |
Sort threads by usage; use --skip-sort
to
disable.
Command-Line Format | --text |
---|---|
Type | Boolean |
Default Value | FALSE |
Display data using text. This option or
--graph
must be true; both
options may be true.
The short form for this option was -x
in
previous versions of NDB Cluster, but this is no longer
supported.
Command-Line Format | --user[=name] |
---|---|
Type | String |
Default Value | root |
Connect as this MySQL user.
Sample Output.
The next figure shows ndb_top running in a
terminal window on a Linux system with an
ndbmtd data node under a moderate load.
Here, the program has been invoked using
ndb_top
-n8
-x
to provide
both text and graph output:
Beginning with NDB 8.0.20, ndb_top also shows spin times for threads, displayed in green.