On this page

• Log Message Format
• Timestamp
• Severity Levels
• Client Data
• Components
• Verbosity Levels

Log Message Format

Starting in MongoDB 3.0, MongoDB includes the severity level and the component associated with each log message. The log messages have the form:

<timestamp> <severity> <component> [<context>] <message>

For example:

2014-11-03T18:28:32.450-0500 I NETWORK [initandlisten] waiting for connections on port 27017

Client operations appear in the log if their duration exceeds the slow operation threshold or when the log verbosity level is 1 or higher. These log entries include the full command object associated with the operation.

The following example output includes information about an aggregation operation:

2017-10-13T10:55:42.935-0700 I COMMAND  [conn1] command test.items appName: "MongoDB Shell" command: aggregate { aggregate: "items", pipeline: [ { $match: { a: { $gte: 4.0 } } } ], cursor: {} } planSummary: COLLSCAN keysExamined:0 docsExamined:5 cursorExhausted:1 numYields:0 nreturned:2 reslen:155 locks:{ Global: { acquireCount: { r: 8 } }, Database: { acquireCount: { r: 4 } }, Collection: { acquireCount: { r: 3 } } } protocol:op_command 0ms

Timestamp

The default format for the <timestamp> is iso8601-local. To modify the timestamp format, use the --timeStampFormat runtime option or the systemLog.timeStampFormat setting.

Severity Levels

The following table lists the severity levels associated with each log message:

You can specify the verbosity level of various components to determine the amount of Informational and Debug messages MongoDB outputs. [1]

To set verbosity levels, see Configure Log Verbosity Levels.

Client Data

Client application debugging and performance monitoring is easier when you can clearly match server events with particular client requests. With this in mind, recent MongoDB drivers and client applications (including the mongo shell) have the ability to send identifying information at the time of connection to the server. After the connection is established, the client does not send the identifying information again unless the connection is dropped and reestablished.

The exact fields included vary by client. Below is a sample client data document:

{
   application: {
     name: "MongoDB Shell"
   },
   driver: {
      name: "MongoDB Internal Client",
      version: "3.4.0"
   },
   os: {
      type: "Darwin",
      name: "Mac OS X",
      architecture: "x86_64",
      version: "15.3.0"
   }
}

When secondary members of a replica set initiate a connection to a primary, they send similar data. A typical connection document is as follows:

{
   driver: {
      name: "NetworkInterfaceASIO-Replication",
      version: "3.4.0"
   },
   os: {
      type: "Darwin",
      name: "Mac OS X",
      architecture: "x86_64",
      version: "15.3.0"
   }
}

For a complete description of client information and required fields, see the MongoDB Handshake specification .

Components

Log messages now include components, providing functional categorization of the messages:

ACCESS

Messages related to access control, such as authentication. To specify the log level for ACCESS components, use the systemLog.component.accessControl.verbosity setting.

COMMAND

Messages related to database commands, such as count. To specify the log level for COMMAND components, use the systemLog.component.command.verbosity setting.

CONTROL

Messages related to control activities, such as initialization. To specify the log level for CONTROL components, use the systemLog.component.control.verbosity setting.

FTDC

New in version 3.2.

Messages related to the diagnostic data collection mechanism, such as server statistics and status messages. To specify the log level for FTDC components, use the systemLog.component.ftdc.verbosity setting.

GEO

Messages related to the parsing of geospatial shapes, such as verifying the GeoJSON shapes. To specify the log level for GEO components, set the systemLog.component.geo.verbosity parameter.

INDEX

Messages related to indexing operations, such as creating indexes. To specify the log level for INDEX components, set the systemLog.component.index.verbosity parameter.

NETWORK

Messages related to network activities, such as accepting connections. To specify the log level for NETWORK components, set the systemLog.component.network.verbosity parameter.

QUERY

Messages related to queries, including query planner activities. To specify the log level for QUERY components, set the systemLog.component.query.verbosity parameter.

REPL

Messages related to replica sets, such as initial sync, heartbeats, steady state replication, and rollback. [1] To specify the log level for REPL components, set the systemLog.component.replication.verbosity parameter.

REPL_HB

Messages related specifically to replica set heartbeats. To specify the log level for REPL_HB components, set the systemLog.component.replication.heartbeats.verbosity parameter.

REPL is the parent component of REPL_HB. If systemLog.component.replication.heartbeats.verbosity is unset, MongoDB uses the REPL verbosity level for REPL_HB components.

ROLLBACK

Messages related to rollback operations. To specify the log level for ROLLBACK components, set the systemLog.component.replication.rollback.verbosity parameter.

REPL is the parent component of ROLLBACK. If systemLog.component.replication.rollback.verbosity is unset, MongoDB uses the REPL verbosity level for ROLLBACK components.

SHARDING

Messages related to sharding activities, such as the startup of the mongos. To specify the log level for SHARDING components, use the systemLog.component.sharding.verbosity setting.

STORAGE

Messages related to storage activities, such as processes involved in the fsync command. To specify the log level for STORAGE components, use the systemLog.component.storage.verbosity setting.

JOURNAL

Messages related specifically to journaling activities. To specify the log level for JOURNAL components, use the systemLog.component.storage.journal.verbosity setting.

STORAGE is the parent component of JOURNAL. If systemLog.component.storage.journal.verbosity is unset, MongoDB uses the STORAGE verbosity level for JOURNAL components.

WRITE

Messages related to write operations, such as update commands. To specify the log level for WRITE components, use the systemLog.component.write.verbosity setting.

-

Messages not associated with a named component. Unnamed components have the default log level specified in the systemLog.verbosity setting. The systemLog.verbosity setting is the default setting for both named and unnamed components.

Verbosity Levels

systemLog:
   verbosity: