OPTIONS

mongotop

Synopsis

mongotop provides a method to track the amount of time a MongoDB instance spends reading and writing data. mongotop provides statistics on a per-collection level. By default, mongotop returns values every second.

See also

For more information about monitoring MongoDB, see Monitoring Database Systems.

For additional background on various other MongoDB status outputs see:

For an additional utility that provides MongoDB metrics see “mongostat.”

Options

mongotop
mongotop
--help

Returns a basic help and usage text.

--verbose, -v

Increases the amount of internal reporting returned on the command line. Increase the verbosity with the -v form by including the option multiple times, (e.g. -vvvvv.)

--version

Print the version of the mongotop utility and exit.

--host <hostname><:port>

Specifies a resolvable hostname for the mongod from which you want to export data. By default mongotop attempts to connect to a MongoDB process running on the localhost port number 27017.

Optionally, specify a port number to connect a MongoDB instance running on a port other than 27017.

To connect to a replica set, you can specify the replica set seed name, and a seed list of set members, in the following format:

<replica_set_name>/<hostname1><:port>,<hostname2:<port>,...
--port <port>

Specifies the port number, if the MongoDB instance is not running on the standard port. (i.e. 27017) You may also specify a port number using the mongotop --host command.

--ipv6

Enables IPv6 support that allows mongotop to connect to the MongoDB instance using an IPv6 network. All MongoDB programs and processes, including mongotop, disable IPv6 support by default.

--username <username>, -u <username>

Specifies a username to authenticate to the MongoDB instance, if your database requires authentication. Use in conjunction with the mongotop option to supply a password.

--password <password>

Specifies a password to authenticate to the MongoDB instance. Use in conjunction with the --username option to supply a username.

If you specify a --username without the --password option, mongotop will prompt for a password interactively.

--locks

New in version 2.2.

Toggles the mode of mongotop to report on use of per-database locks. These data are useful for measuring concurrent operations and lock percentage.

<sleeptime>

The final argument is the length of time, in seconds, that mongotop waits in between calls. By default mongotop returns data every second.

Fields

mongotop returns time values specified in milliseconds (ms.)

mongotop only reports active namespaces or databases, depending on the --locks option. If you don’t see a database or collection, it has received no recent activity. You can issue a simple operation in the mongo shell to generate activity to affect the output of mongotop.

mongotop.ns

Contains the database namespace, which combines the database name and collection.

Changed in version 2.2: If you use the --locks, the ns field does not appear in the mongotop output.

mongotop.db

New in version 2.2.

Contains the name of the database. The database named . refers to the global lock, rather than a specific database.

This field does not appear unless you have invoked mongotop with the --locks option.

mongotop.total

Provides the total amount of time that this mongod spent operating on this namespace.

mongotop.read

Provides the amount of time that this mongod spent performing read operations on this namespace.

mongotop.write

Provides the amount of time that this mongod spent performing write operations on this namespace.

mongotop.<timestamp>

Provides a time stamp for the returned data.

Use

By default mongotop connects to the MongoDB instance running on the localhost port 27017. However, mongotop can optionally connect to remote mongod instances. See the mongotop options for more information.

To force mongotop to return less frequently specify a number, in seconds at the end of the command. In this example, mongotop will return every 15 seconds.

mongotop 15

This command produces the following output:

connected to: 127.0.0.1

                    ns       total        read       write           2012-08-13T15:45:40
test.system.namespaces         0ms         0ms         0ms
  local.system.replset         0ms         0ms         0ms
  local.system.indexes         0ms         0ms         0ms
  admin.system.indexes         0ms         0ms         0ms
                admin.         0ms         0ms         0ms

                    ns       total        read       write           2012-08-13T15:45:55
test.system.namespaces         0ms         0ms         0ms
  local.system.replset         0ms         0ms         0ms
  local.system.indexes         0ms         0ms         0ms
  admin.system.indexes         0ms         0ms         0ms
                admin.         0ms         0ms         0ms

To return a mongotop report every 5 minutes, use the following command:

mongotop 300

To report the use of per-database locks, use mongotop --locks, which produces the following output:

$ mongotop --locks
connected to: 127.0.0.1

                  db       total        read       write          2012-08-13T16:33:34
               local         0ms         0ms         0ms
               admin         0ms         0ms         0ms
                   .         0ms         0ms         0ms
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