Mongo.getWriteConcern.txt

=======================
Mongo.getWriteConcern()
=======================

.. default-domain:: mongodb

.. contents:: On this page
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   :class: singlecol

Definition
----------

.. method:: Mongo.getWriteConcern()

   :returns: The current :term:`write concern` for the :method:`Mongo()
             <db.getMongo()>` connection object.

   See the :ref:`write-concern` for an introduction to write concerns
   in MongoDB.

Compatibility
-------------

This method is available in deployments hosted in the following environments: 

.. include:: /includes/fact-environments-atlas-only.rst

.. include:: /includes/fact-environments-onprem-only.rst

Syntax
------

The command takes the following form:

.. code-block:: javascript

   db.getMongo().getWriteConcern()

This operation returns a document with the following values:

.. code-block:: javascript
   :copyable: false

   { w: <value>, wtimeout: <number>, j: <boolean> }

The fields are: 

.. list-table::
   :header-rows: 1

   * - Field
     - Description

   * - ``w``
     - The number of :binary:`~bin.mongod` or :binary:`~bin.mongod`
       instances that must acknowledge a write. Possible values are:

       - "majority". A majority of the target instances must
         acknowledge the write.
       - <number>. The specified number of target instances must
         acknowledge the write.
       - <custom write concern name>. A user defined write concern, the
         tagged instances must acknowledge the write.

       See :ref:`write concern specification <wc-w>` for details.

   * -  ``j``
     - A boolean value. ``j: true`` requests acknowledgment that the
       write operation has been written to the :ref:`on-disk journal
       <journaling-internals>`.
     
   * - ``wtimeout``
     - The number of milliseconds to wait for acknowledgment of the
       write concern. ``wtimeout`` is only applicable when ``w`` has a
       value greater than ``1``.

Example
-------

To return the current write concern, enter the following:

.. code-block:: javascript

   db.getMongo().getWriteConcern()

When a write concern is specified using
:method:`Mongo.setWriteConcern()`, the output of
``Mongo.getWriteConcern()`` is similar to:

.. code-block:: javascript

   WriteConcern { w: 2, wtimeout: 1000, j: true }

The ``Mongo.getWriteConcern()`` command returns an empty line if no
write concern has been specified. 

.. seealso::

   - :method:`~Mongo.setWriteConcern()`