.. _version_4.2.5:

=============
Version 4.2.5
=============

Released on 2020-09-22.

.. NOTE::

    If you are upgrading a cluster, you must be running CrateDB 4.0.2 or higher
    before you upgrade to 4.2.5.

    We recommend that you upgrade to the latest 4.1 release before moving to
    4.2.5.

    A rolling upgrade from 4.1.7+ to 4.2.5 is supported.

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

.. _back up your data: https://crate.io/docs/crate/reference/en/latest/admin/snapshots.html



.. rubric:: Table of Contents

.. contents::
   :local:


See the :ref:`version_4.2.0` release notes for a full list of changes in the
4.2 series.


Fixes
=====

- Fixed an issue that caused the IP restriction in the host based
  authentication to not work correctly in all cases

- Fixed a BWC issue with :ref:`aggregation functions <aggregation-functions>`
  resolving in a mixed version cluster where at least one node is on version <
  4.2.

- Improved the throttling behavior of ``INSERT INTO .. <query>``, it is now
  more aggressive to reduce the amount of memory used by a ``INSERT INTO``
  operation.

- Fixed an issue which resulted in an error when a parameter symbol
  (placeholder) is used inside an aggregation.

- Fixed an issue that could lead to the incorrect result of joining more than
  two tables even if the join condition is satisfied. Only the hash join
  implementation was affected by the issue.

- Fixed a regression introduced in 4.2.3 that prevented primary key lookups
  with parameter placeholders from working in some cases.

- Fixed an issue resulting wrongly in a `RED` ``sys.health.health`` state for
  healthy partitions with less shards configured than the actual partitioned
  table.

- Fixed the resulting value for ``sys.health.partition_ident`` for
  non-partitioned tables. As documented, a `NULL` value should be returned
  instead of an empty string.

- Fixed a performance regression that caused unnecessary traffic and load to
  the active master node when processing ``INSERT`` statements.
