clear-jumbo-flag.txt

====================
Clear ``jumbo`` Flag
====================

.. default-domain:: mongodb

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If MongoDB cannot split a chunk that exceeds the :ref:`specified chunk
size <sharding-chunk-size>` or contains a number of documents that
exceeds the :limit:`max <Maximum Number of Documents Per Chunk to
Migrate>`, MongoDB labels the chunk as :ref:`jumbo <jumbo-chunks>`.

If the chunk size no longer hits the limits, MongoDB clears the
``jumbo`` flag for the chunk when the :program:`mongos` reloads or
rewrites the chunk metadata.

In cases where you need to clear the flag manually, the following
procedures outline the steps to manually clear the ``jumbo`` flag.

Procedures
----------

.. _preferred-method-clear-jumbo:

Divisible Chunks
~~~~~~~~~~~~~~~~

The preferred way to clear the ``jumbo`` flag from a chunk is to
attempt to split the chunk. If the chunk is divisible, MongoDB removes
the flag upon successful split of the chunk.

.. include:: /includes/steps/clear-jumbo-flag-preferred.rst

Indivisible Chunks
~~~~~~~~~~~~~~~~~~

In some instances, MongoDB cannot split the no-longer ``jumbo`` chunk,
such as a chunk with a range of single shard key value, and the
preferred method to clear the flag is not applicable. In such cases,
you can clear the flag using the following steps.

.. important::

   Only use this method if the :ref:`preferred method
   <preferred-method-clear-jumbo>` is *not* applicable.

   Before modifying the :doc:`config database
   </reference/config-database>`, *always* back up the config database.

If you clear the ``jumbo`` flag for a chunk that still exceeds the
chunk size and/or the document number limit, MongoDB will re-label the
chunk as ``jumbo`` when MongoDB tries to move the chunk.

.. include:: /includes/steps/clear-jumbo-flag.rst