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This is an upcoming (i.e. in progress) version of the 4.4 MongoDB Database Tools Documentation.

See the MongoDB 4.2 Manual for documentation on the 4.2 database tools

mongotop

Description

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

mongotop releases as version 100 and has an independent release schedule from the MongoDB Server. Previously, mongotop was released alongside the MongoDB Server and used matching versioning.

Note

This documentation is for version 100 of mongotop.

For documentation on the MongoDB 4.2 or earlier versions of mongotop, reference the MongoDB Server Documentation for that version of the tool:

Quick links to older documentation

Run mongotop from the system command line, not the mongo shell.

Availability

The mongotop tool is part of the MongoDB Database Tools package. You can install the MongoDB Database Tools package in one of two ways:

  1. Follow the installation guide for your platform to install the MongoDB Database Tools as part of a MongoDB Server installation. The MongoDB Database Tools are included with both Community Edition and Enterprise Edition installations.
  2. Download the MongoDB Database Tools separately from the MongoDB Download Center, either as a separate mongodb-database-tools download, or contained within the TGZ or ZIP downloads, depending on platform. On Windows, the MSI installer includes all tools as part of the default installation.

Compatibility

The mongotop supports the following versions of the MongoDB Server:

  • MongoDB 4.4
  • MongoDB 4.2
  • MongoDB 4.0
  • MongoDB 3.6

While mongotop may work on earlier versions of MongoDB server, any such compatibility is not guaranteed.

Syntax

Run mongotop from the system command line, not the mongo shell.

Default

mongotop [frequency]

You can run mongotop without any command-line options to connect to the mongod instance running on the localhost port 27017. By default, mongotop returns values every second.

mongotop

To have mongotop report every 30 seconds, specify the time:

mongotop 30

When connected to a mongod instance, the program reports first on the connection and then reports on the statistics at the configured frequency.

2019-04-29T15:35:27.785-0400 connected to: 127.0.0.1

             ns    total      read      write    <timestamp>
<db.collection>    81802ms     0ms    81802ms
...

Command Line Options

mongotop [options] [frequency]

You can run mongotop with various command-line options.

For example, to connect mongotop to a mongod instance running on a remote host mongodb0.example.com and report every 30 seconds:

  • You can include the desired frequency of reporting (in this example, 30 seconds) and the --uri option to specify the host and port:

    mongotop 30 --uri='mongodb://mongodb0.example.com:27017' [additional options]
    

    If the mongod instance requires authentication, you can specify the user, password, and authentication database as part of the URI connection string:

    mongotop 30 --uri='mongodb://user:password@mongodb0.example.com:27017/?authSource=admin' [additional options]
    

    The user running mongotop must have the serverStatus and top privileges.

    For more information on the URI connection string, see --uri.

  • Alternatively, you can use the --host and --port options to specify the host and port:

    mongotop 30 --host=mongodb0.example.com --port=27017 [additional options]
    

    If the mongod instance requires authentication, you can specify the user -u, and the authentication database --authenticationDatabase. Omit the --password option to have mongoexport prompt for the password.

    mongotop 30 --host=mongodb0.example.com --port=27017 -u=user --authenticationDatabase=admin [additional options]
    

    The user running mongotop must have the serverStatus and top privileges.

For more information on the options available, see Options.

When connected to a mongod instance, the program reports first on the connection and then reports on the statistics at the configured frequency.

2019-04-29T15:35:27.785-0400 connected to: 127.0.0.1

             ns    total      read      write    <timestamp>
<db.collection>    81802ms     0ms    81802ms
...

Required Access

In order to connect to a mongod that enforces authorization, the connecting user must have the serverStatus and top privileges.

The built-in role clusterMonitor provides these privileges.

Behavior

FIPS

mongotop automatically creates FIPS-compliant connections to a mongod/mongos that is configured to use FIPS mode.

Options

mongotop
--help

Returns information on the options and use of mongotop.

--verbose, -v

Increases the amount of internal reporting returned on standard output or in log files. Increase the verbosity with the -v form by including the option multiple times, (e.g. -vvvvv.)

--quiet

Runs mongotop in a quiet mode that attempts to limit the amount of output.

This option suppresses:

  • output from database commands
  • replication activity
  • connection accepted events
  • connection closed events
--version

Returns the mongotop release number.

--uri=<connectionString>

Specify a resolvable URI connection string (enclose in quotes) to connect to the MongoDB deployment.

--uri="mongodb://[username:password@]host1[:port1][,host2[:port2],...[,hostN[:portN]]][/[database][?options]]"

For information on the components of the connection string, see the Connection String URI Format documentation.

Note

For TLS/SSL options, use the command-line options instead of the URI options for TLS/SSL (Available starting in 4.2).

Important

The following command-line options cannot be used in conjunction with --uri option:

Instead, specify these options as part of your --uri connection string.

--host=<hostname><:port>, -h=<hostname><:port>

Default: localhost:27017

Specifies a resolvable hostname for the mongod to which to connect. By default, the mongotop attempts to connect to a MongoDB instance running on the localhost on port number 27017.

To connect to a replica set, specify the replSetName and a seed list of set members, as in the following:

--host=<replSetName>/<hostname1><:port>,<hostname2><:port>,<...>

When specifying the replica set list format, mongotop always connects to the primary.

You can also connect to any single member of the replica set by specifying the host and port of only that member:

--host=<hostname1><:port>

If you use IPv6 and use the <address>:<port> format, you must enclose the portion of an address and port combination in brackets (e.g. [<address>]).

Note

You cannot specify both --host and --uri.

If connected to a replica set where the primary is not reachable, mongotop returns an error message.

--port=<port>

Default: 27017

Specifies the TCP port on which the MongoDB instance listens for client connections.

Note

You cannot specify both --port and --uri.

--ssl

Enables connection to a mongod or mongos that has TLS/SSL support enabled.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients.

--sslCAFile=<filename>

Specifies the .pem file that contains the root certificate chain from the Certificate Authority. Specify the file name of the .pem file using relative or absolute paths.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients.

--sslPEMKeyFile=<filename>

Specifies the .pem file that contains both the TLS/SSL certificate and key. Specify the file name of the .pem file using relative or absolute paths.

This option is required when using the --ssl option to connect to a mongod or mongos that has CAFile enabled without allowConnectionsWithoutCertificates.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients.

--sslPEMKeyPassword=<value>

Specifies the password to de-crypt the certificate-key file (i.e. --sslPEMKeyFile). Use the --sslPEMKeyPassword option only if the certificate-key file is encrypted. In all cases, the mongotop will redact the password from all logging and reporting output.

If the private key in the PEM file is encrypted and you do not specify the --sslPEMKeyPassword option, the mongotop will prompt for a passphrase. See TLS/SSL Certificate Passphrase.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients.

--sslCRLFile=<filename>

Specifies the .pem file that contains the Certificate Revocation List. Specify the file name of the .pem file using relative or absolute paths.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients.

--sslAllowInvalidCertificates

Bypasses the validation checks for server certificates and allows the use of invalid certificates. When using the allowInvalidCertificates setting, MongoDB logs as a warning the use of the invalid certificate.

Warning

Although available, avoid using the --sslAllowInvalidCertificates option if possible. If the use of --sslAllowInvalidCertificates is necessary, only use the option on systems where intrusion is not possible.

Connecting to a mongod or mongos instance without validating server certificates is a potential security risk. If you only need to disable the validation of the hostname in the TLS/SSL certificates, see --sslAllowInvalidHostnames.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients.

--sslAllowInvalidHostnames

Disables the validation of the hostnames in TLS/SSL certificates. Allows mongotop to connect to MongoDB instances even if the hostname in their certificates do not match the specified hostname.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients.

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

Specifies a username with which to authenticate to a MongoDB database that uses authentication. Use in conjunction with the --password and --authenticationDatabase options.

Note

You cannot specify both --username and --uri.

--password=<password>, -p=<password>

Specifies a password with which to authenticate to a MongoDB database that uses authentication. Use in conjunction with the --username and --authenticationDatabase options.

To prompt the user for the password, pass the --username option without --password or specify an empty string as the --password value, as in --password "" .

Note

You cannot specify both --password and --uri.

--authenticationDatabase=<dbname>

Specifies the authentication database where the specified --username has been created. --authenticationDatabase is required for mongod and mongos instances that use Authentication. See Authentication Database.

Note

You cannot specify both --authenticationDatabase and --uri.

--authenticationMechanism=<name>

Default: SCRAM-SHA-1

Specifies the authentication mechanism the mongotop instance uses to authenticate to the mongod or mongos.

Value Description
SCRAM-SHA-1 RFC 5802 standard Salted Challenge Response Authentication Mechanism using the SHA-1 hash function.
SCRAM-SHA-256

RFC 7677 standard Salted Challenge Response Authentication Mechanism using the SHA-256 hash function.

Requires featureCompatibilityVersion set to 4.0.

MONGODB-X509 MongoDB TLS/SSL certificate authentication.
GSSAPI (Kerberos) External authentication using Kerberos. This mechanism is available only in MongoDB Enterprise.
PLAIN (LDAP SASL) External authentication using LDAP. You can also use PLAIN for authenticating in-database users. PLAIN transmits passwords in plain text. This mechanism is available only in MongoDB Enterprise.

Note

You cannot specify both --authenticationMechanism and --uri.

--gssapiServiceName=<serviceName>

Specify the name of the service using GSSAPI/Kerberos. Only required if the service does not use the default name of mongodb.

This option is available only in MongoDB Enterprise.

--gssapiHostName=<hostname>

Specify the hostname of a service using GSSAPI/Kerberos. Only required if the hostname of a machine does not match the hostname resolved by DNS.

This option is available only in MongoDB Enterprise.

--locks

Toggles the mode of mongotop to report on use of per-database locks. This data is only available when connected to a MongoDB 2.6 or older instance.

--locks returns an error when called against a mongod 3.0 or newer instance that does not report per-database lock usage.

--rowcount=<int>, -n=<int>

Number of lines of data that mongotop should print. “0 for indefinite”

--json

Returns output for mongotop in JSON format.

<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

When connected to a mongod instance, the program reports first on the connection and then reports on the statistics at the configured frequency. mongotop returns time values specified in milliseconds (ms.)

2019-04-29T15:35:27.785-0400 connected to: 127.0.0.1

             ns    total      read      write    <timestamp>
<db.collection>    81802ms     0ms    81802ms
...

             ns    total      read      write    <timestamp>
<db.collection>    0ms         0ms        0ms
...

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.

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

mongotop.db

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.

Examples

Run mongotop from the system command line, not the mongo shell.

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:

2019-04-29T15:35:27.785-0400 connected to: 127.0.0.1


                    ns    total    read    write    2019-04-29T15:35:57-04:00
    admin.system.roles      0ms     0ms      0ms
    admin.system.users      0ms     0ms      0ms
  admin.system.version      0ms     0ms      0ms
config.system.sessions      0ms     0ms      0ms
     local.startup_log      0ms     0ms      0ms
  local.system.replset      0ms     0ms      0ms

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

mongotop 300

Additional Information

For more information about monitoring MongoDB, see Monitoring for MongoDB.

For additional background on various other MongoDB status outputs see:

For an additional utility that provides MongoDB metrics see mongostat.

←   mongostat mongofiles  →