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:

Level Description
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

To configure the log verbosity level:

To specify a verbosity level when starting mongosqld, use the -v option. Repeating v increases the verbosity level.


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

mongosqld --schema schema.drdl --auth -vv

To learn more about the verbosity levels and how to use them, see --verbose.

Log Filename Format

New in version 2.5.

If you direct mongosqld to rotate log files with the --logRotate option, BI Connector adds a sequence number to ensure the uniqueness of each new log file name. Log files have the following format:


For example:


For more information on log file rotation, see the --logRotate option.