Log Messages

mongosqld log messages have the form:

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

For example:

2017-08-17T13:34:48.910-0700 I NETWORK [initandlisten] waiting for connections at


Log messages use iso8601 format for the timestamp, with a UTC offset set by the server on which mongosqld is running.

Severity Levels

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

Level Description
F Fatal
E Error
W Warning
I Informational, for Verbosity Level of 0
D Debug, for All Verbosity Levels > 0

The default log verbosity level is 0, which includes all non-Debug messages. Increasing the verbosity level adds additional Debug messages to the logs. To set the verbosity level, see Configure Log Verbosity Levels.


Log messages include a component field, providing functional categorization of the messages:


Messages related to control activities, such as initialization.


Messages related to network activities, such as accepting connections.


Messages related to query plan generation.


Messages related to query plan optimization.


Messages related to query execution.

Configure Log Verbosity Level

You can configure the log verbosity level either by including a verbosity parameter when starting mongosqld from the command line, or by specifying systemLog.verbosity in a configuration file.

To specify a verbosity level when starting mongosqld, use the -v option. -v sets the verbosity level to 1, while -vv sets it to 2, and so on up the maximum level of 5.

The following invocation of mongosqld sets the log verbosity level to 3.

mongosqld --schema schema.drdl --auth -vvv

Alternatively, you can specify an integer value with the --verbose option. The following invocation of mongosqld sets the log verbosity level to 2.

mongosqld --schema schema.drdl --auth --verbose=2