db.collection.validate.txt

========================
db.collection.validate()
========================

.. default-domain:: mongodb

.. contents:: On this page
   :local:
   :backlinks: none
   :depth: 1
   :class: singlecol

.. include:: includes/wayfinding/mongosh-method-validate.rst

.. _validate-standalone-inconsistencies:

Description
-----------

.. versionchanged:: 6.2

.. method:: db.collection.validate(<documents>)

   .. |dbcommand| replace:: :dbcommand:`validate` command

   Validates a collection. The method scans a collection data and
   indexes for correctness and returns the result. For details of the
   output, see :ref:`validate-output`.

   Starting in version 5.0, the :method:`db.collection.validate()`
   method can also fix inconsistencies in the collection.
   
   .. include:: /includes/fact-validate-standalone-inconsistencies.rst

   The :method:`db.collection.validate()` method is a wrapper around
   the :dbcommand:`validate` command.


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

.. |command| replace:: method

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

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

.. include:: /includes/fact-environments-atlas-support-all.rst

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

Syntax
------

The :method:`db.collection.validate()` method has the following syntax:

.. code-block:: javascript

   db.collection.validate( { 
      full: <boolean>,  // Optional
      repair: <boolean>,  // Optional, added in MongoDB 5.0
      checkBSONConformance: <boolean>  // Optional, added in MongoDB 6.2
   } )

Parameters
~~~~~~~~~~

The :method:`db.collection.validate()` method can take the
following optional document parameter with the fields:

.. list-table::
   :header-rows: 1
   :widths: 15 15 70

   * - Field
     - Type
     - Description

   * - :ref:`full <method-validate-full>`
     - boolean

     - .. _method-validate-full:
     
       *Optional*. A flag that determines whether the command performs
       a slower but more thorough check or a faster but less thorough
       check.

       - If ``true``, performs a more thorough check with the following
         exception:

         - Full validation on the ``oplog`` for WiredTiger skips the more 
           thorough check.

       - If ``false``, omits some checks for a faster but less
         thorough check.

       The default is ``false``.

       .. include:: /includes/fact-validate-wiredtiger-full-option.rst

   * - :ref:`repair <method-validate-repair>`
     - boolean

     - .. _method-validate-repair:

       .. include:: /includes/fact-validate-repair-option.rst

   * - ``fixMultikey`` 
     - boolean
     - .. _method-validate-fixmultikey:

       .. include:: /includes/fact-validate-fixmultikey.rst

   * - :ref:`checkBSONConformance
       <method-validate-checkBSONConformance>`
     - boolean
     - .. _method-validate-checkBSONConformance:

       .. include:: /includes/fact-validate-conformance.rst

Behavior
--------

Performance
~~~~~~~~~~~

The :method:`db.collection.validate()` method is potentially resource
intensive and may impact the performance of your MongoDB instance,
particularly on larger data sets.

The :method:`db.collection.validate()` method obtains an exclusive lock
on the collection. This will block all reads and writes on the
collection until the operation finishes. When run on a secondary, the
operation can block all other operations on that secondary until it
finishes.

.. warning::

   Validation has exclusive lock requirements that affect performance
   on primaries and on secondaries that are servicing reads. Consider
   only running :method:`db.collection.validate()` on nodes that are
   not servicing reads or writes.

   To minimize impact on the primary, the majority of the data-bearing
   (non-arbiter), voting members in the cluster must be available and
   must not have significant replication lag.

   To minimize the impact of the validation operation on client
   applications, run :method:`db.collection.validate()` on a secondary
   node that is not servicing read requests. You can convert the
   current primary node to a secondary node, by running the
   :method:`rs.stepDown()` method.

   To completely isolate the :method:`db.collection.validate()`
   operation from client traffic, choose one of the following options:
   
   - Isolate a replica set member by following the :ref:`rolling
     maintenance procedure <perform-maint-on-replica-set>` to
     temporarily remove it from the cluster.
   - :ref:`Convert a secondary node
     <configure-hidden-replica-set-member>` to a replica set
     :ref:`hidden member <replica-set-hidden-members>` and perform the
     validation on the hidden node.

Data Throughput Metrics
~~~~~~~~~~~~~~~~~~~~~~~

.. include:: /includes/extracts/4.4-validate-data-throughput.rst

Collection Validation Improvements
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. include:: /includes/validate-improvements-introduction.rst

Examples
--------

- To validate a collection ``myCollection`` using the default validation
  setting (specifically, :ref:`full: false <method-validate-full>`):

  .. code-block:: javascript

     db.myCollection.validate()

     db.myCollection.validate({ })

     db.myCollection.validate( { full: false } )

- To perform a full validation of collection ``myCollection``, specify
  :ref:`full: true <method-validate-full>`:

  .. code-block:: javascript

     db.myCollection.validate( { full: true } )

- To repair collection ``myCollection``, specify
  :ref:`repair: true <method-validate-repair>`:

  .. code-block:: javascript

     db.myCollection.validate( { repair: true } )

- To perform additional BSON conformance checks in ``myCollection``,
  specify :ref:`checkBSONConformance: true
  <method-validate-checkBSONConformance>`:

  .. code-block:: javascript

    db.myCollection.validate( { checkBSONConformance: true } )

For details of the output, see :ref:`validate-output`.