Starting and stopping

After installation, the FoundationDB Document Layer is set to start automatically. You can manually start and stop the layer with the commands shown below.

These commands start and stop the master fdbdocmonitor process, which in turn starts fdbdoc processes.


On Linux, the Document Layer is started and stopped using the service command as follows:

$ sudo service fdb-document-layer start
$ sudo service fdb-document-layer stop

On Ubuntu, it can be prevented from starting at boot as follows (without stopping the service):

$ sudo update-rc.d fdb-document-layer disable

On RHEL/CentOS, it can be prevented from starting at boot as follows (without stopping the service):

$ sudo chkconfig fdb-document-layer off 


On macOS, the Document Layer is started and stopped using launchctl as follows:

$ sudo launchctl load /Library/LaunchDaemons/com.foundationdb.fdbdocmonitor.plist
$ sudo launchctl unload /Library/LaunchDaemons/com.foundationdb.fdbdocmonitor.plist

It can be stopped and prevented from starting at boot as follows:

$ sudo launchctl unload -w /Library/LaunchDaemons/com.foundationdb.fdbdocmonitor.plist

fdbdocmonitor and fdbdoc

The core Document Layer server process is fdbdoc. Each fdbdoc process uses up to one full CPU core.

To make configuring, starting, stopping, and restarting fdbdoc processes easy, the Document Layer also comes with a singleton daemon process, fdbdocmonitor, which is started automatically on boot. fdbdocmonitor reads the document.conf file and starts the configured set of fdbdoc processes.

Whenever the document.conf file changes, the fdbdocmonitor daemon automatically detects the changes and starts, stops, or restarts child processes as necessary.

During normal operation, fdbdocmonitor is transparent, and you interact with it only by modifying the configuration in document.conf and perhaps occasionally by starting and stopping it manually. If some problem prevents an fdbdoc process from starting or causes it to stop unexpectedly, fdbdocmonitor will log errors to the system log.

Managing trace files

By default, trace files are output to:

### Linux


### macOS


Trace files are rolled every 10MB. These files are valuable to the FoundationDB team for support and diagnostic purposes and should be retained. Old trace files are automatically deleted so that there are no more than 100 MB worth of trace files per process. The size of each log file and the maximum total size of the log files are configurable on a per process basis in the configuration file.

Slow query log

If slow query logging has been enabled in the configuration file (as it is by default), then any application queries that result in full collection scans will be logged to the current trace file.

If logs are written to the default location, then a list of all slow queries present in the logs can be recovered with the following command:

### Linux

grep SlowQuery /var/log/foundationdb/document/fdbdoc-trace*

### macOS

grep SlowQuery /usr/local/foundationdb/document/logs/fdbdoc-trace*

Future versions of the Document Layer may use a different storage format or storage location for slow query logging. Any changes in this functionality will be included in the relevant release notes.

MongoDB® administrative commands

Due to the Document Layer’s unique architecture, replication and sharding operations are entirely invisible to users and administrators. A significant benefit of this approach is that the Document Layer does not need to provide additional commands such as those described in Replication Commands or Sharding Commands in MongoDB®.

Document Layer does not have any authentication framework yet. So, we don’t support any of ‘Authentication Commands’, ‘User Management Commands,’ and ‘Role Management Commands’. We are going to add TLS based authentication very soon.

Among the ‘Instance Administration Commands,’ the following are supported: create, dropDatabase, dropIndexes, drop, and renameCollection. Many of the remaining commands concern issues with MongoDB® operation that administrators of the Document Layer don’t need to consider (e.g. fsync, compact) and so are unlikely to be implemented unless they prove necessary to provide compatibility with a framework, ODM, or legacy software.

The following ‘Diagnostic Commands’ are implemented or partially implemented: buildInfo, dbStats, collStats, listDatabases, ping, whatsmyuri. If you would like to see another diagnostic command implemented or made more detailed, please tell us about it so we can prioritize this work.

Additionally, the Document Layer has added the following database commands that are not present in MongoDB®: beginTransaction, commitTransaction, rollbackTransaction, getDocLayerVersion, and getKVStatus.


To uninstall the Document Layer from a cluster of one or more machines:

  1. Uninstall the packages on each machine in the cluster.


    $ sudo dpkg -P fdb-document-layer


    $ sudo rpm -e fdb-document-layer


    $ sudo /usr/local/foundationdb/document/
  2. Remove the key-value pairs stored by the Document Layer in the Key-Value store. Connect to the appropriate cluster with one of the Key-Value store language bindings, and remove the directory which contains the state for the Document Layer (defaults to document). Here is an example using Python:

    import fdb
    db =
    dl = fdb.DirectoryLayer()
    dl.remove_if_exists(db, ["document"])