.. _version_2.3.9:

=============
Version 2.3.9
=============

Released on 2018/05/17.

.. NOTE::

    If you are upgrading a cluster, you must be running CrateDB
    :ref:`version_1.1.3` or higher before you upgrade to 2.3.9.

    If you want to perform a `rolling upgrade`_, your current CrateDB version
    number must be at least :ref:`version_2.3.0`. Any upgrade from a version
    prior to this will require a `full restart upgrade`_.

.. WARNING::

    Before upgrading, you should `back up your data`_.

.. _rolling upgrade: https://crate.io/docs/crate/howtos/en/latest/admin/rolling-upgrade.html
.. _full restart upgrade: https://crate.io/docs/crate/howtos/en/latest/admin/full-restart-upgrade.html
.. _back up your data: https://crate.io/docs/crate/reference/en/latest/admin/snapshots.html

.. rubric:: Table of contents

.. contents::
   :local:

Changelog
=========

Fixes
-----

- Fixed a stack overflow exception on upserts which could be caused by retries
  on version conflicts.

- Fixed a memory leak caused by using the ``hyperloglog_distinct`` function.
