~ Licensed to the Apache Software Foundation (ASF) under one
~ or more contributor license agreements. See the NOTICE file
~ distributed with this work for additional information
~ regarding copyright ownership. The ASF licenses this file
~ to you under the Apache License, Version 2.0 (the
~ "License"); you may not use this file except in compliance
~ with the License. You may obtain a copy of the License at
~
~ http://www.apache.org/licenses/LICENSE-2.0
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~ Unless required by applicable law or agreed to in writing,
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~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
~ KIND, either express or implied. See the License for the
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~ under the License.
-->
<!--Replace {{DRUIDVERSION}} with the correct Druid version.-->
Apache Druid {{DRUIDVERSION}} contains over $NUMBER_FEATURES new features, bug fixes, performance enhancements, documentation improvements, and additional test coverage from $NUMBER_OF_CONTRIBUTORS contributors.
<!--
Replace {{MILESTONE}} with the correct milestone number. For example: https://github.com/apache/druid/issues?q=is%3Aclosed+milestone%3A28.0+sort%3Aupdated-desc+
-->
See the [complete set of changes](https://github.com/apache/druid/issues?q=is%3Aclosed+milestone%3A{{MILESTONE}}+sort%3Aupdated-desc+) for additional details, including bug fixes.
Review the [upgrade notes](#upgrade-notes) and [incompatible changes](#incompatible-changes) before you upgrade to Druid {{DRUIDVERSION}}.
If you are upgrading across multiple versions, see the [Upgrade notes](upgrade-notes.md) page, which lists upgrade notes for the most recent Druid versions.
<!--
This file is a collaborative work in process. Adding a release note to this file doesn't guarantee its presence in the next release until the release branch is cut and the release notes are finalized.
This file contains the following sections:
- Important features, changes, and deprecations
- Functional area and related changes
- Upgrade notes and incompatible changes
Please add your release note to the appropriate section and include the following:
- Detailed title
- Summary of the changes (a couple of sentences) aimed at Druid users
- Link to the associated PR
If your release note contains images, put the images in the release-info/assets folder.
For tips about how to write a good release note, see [Release notes](https://github.com/apache/druid/blob/master/CONTRIBUTING.md#release-notes).
-->
## Important features, changes, and deprecations
This section contains important information about new and existing features.
## Functional area and related changes
This section contains detailed release notes separated by areas.
<!--Carry this forward until 32. Then move it to incompatible changes -->
In Druid 32.0.0, the front coded dictionaries feature will be turned on by default. Front-coded dictionaries reduce storage and improve performance by optimizing for strings where the front part looks similar.
Once this feature is on, you cannot easily downgrade to an earlier version that does not support the feature.
For more information, see [Migration guide: front-coded dictionaries](./migr-front-coded-dict.md).
If you're already using this feature, you don't need to take any action.
