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   <h2>
     Release 1.28.0
     <a href="/news/2021/10/19/release-1.28.0/" class="permalink" title="Permalink">∞</a>
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       release
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       19 Oct 2021
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     <a href="http://people.apache.org/~jhyde" class="post-author">
       <img src="https://github.com/julianhyde.png" class="avatar" alt="jhyde avatar" width="24" height="24">
       jhyde
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     <!--

 -->

 <p>The <a href="">Apache Calcite PMC</a>
 is pleased to announce
 <a href="/docs/history.html#v1-28-0">Apache Calcite release 1.28.0</a>.</p>

 <p>This release comes four months after <a href="/docs/history.html#v1-27-0">1.27.0</a>,
 contains contributions from 38 authors,
 and resolves 76 issues.
 New features include the
 <a href="https://issues.apache.org/jira/browse/CALCITE-4486">UNIQUE</a>
 sub-query predicate, the
 <a href="https://issues.apache.org/jira/browse/CALCITE-4661">MODE</a> aggregate function,
 <a href="https://issues.apache.org/jira/browse/CALCITE-4644">PERCENTILE_CONT and PERCENTILE_DISC</a>
 inverse distribution functions, an
 <a href="https://issues.apache.org/jira/browse/CALCITE-4614">Exasol dialect</a>
 for the JDBC adapter, and improvements to
 <a href="https://issues.apache.org/jira/browse/CALCITE-4779">materialized</a>
 <a href="https://issues.apache.org/jira/browse/CALCITE-3935">view</a>
 <a href="https://issues.apache.org/jira/browse/CALCITE-4774">recognition</a>.</p>

 <p>This release contains some breaking changes (described below) due to the
 <a href="https://issues.apache.org/jira/browse/CALCITE-4787">replacement of ImmutableBeans with Immutables</a>.
 Two APIs are deprecated and will be
 <a href="/docs/history.html#to-be-removed-in-1-29-0">removed in release 1.29</a>.</p>

 <h2 id="breaking-changes-to-immutablebeans">Breaking changes to ImmutableBeans</h2>

 <p>In 1.28, Calcite converted the recently introduced
 <a href="https://issues.apache.org/jira/browse/CALCITE-3328">configuration system</a>
 from an internal system based on
 <a href="https://github.com/apache/calcite/blob/main/core/src/main/java/org/apache/calcite/util/ImmutableBeans.java">ImmutableBeans</a>
 to instead use the <a href="https://immutables.github.io/">Immutables</a>
 annotation processor. This library brings a large number of additional
 features that should make value-type classes in Calcite easier to
 build and leverage. It also reduces reliance on dynamic proxies, which
 should improve performance and reduce memory footprint. Lastly, this
 change increases compatibility with ahead-of-time compilation
 technologies such as <a href="https://www.graalvm.org/">GraalVM</a>. As part of
 this change, a number of minor changes have been made and key methods
 and classes have been deprecated. The change was designed to minimize
 disruption to existing consumers of Calcite but the following minor
 changes needed to be made:</p>
 <ul>
   <li>The
 <a href="https://github.com/apache/calcite/blob/main/core/src/main/java/org/apache/calcite/plan/RelRule.java#L125">RelRule.Config.EMPTY</a>
 field is now deprecated. To create a new configuration subclass, you
 can either use your preferred interface-implementation based
 construction or you can leverage Immutables. To do the latter,
 <a href="https://immutables.github.io/getstarted.html">configure your project</a>
 to use the Immutables annotation processor and annotate your
 subclass with the
 <a href="https://immutables.github.io/immutable.html#value"><code class="language-plaintext highlighter-rouge">@Value.Immutable</code></a>
 annotation.</li>
   <li>Where <code class="language-plaintext highlighter-rouge">RelRule.Config</code> subclasses were nested 2+ classes deep, the
 interfaces have been marked deprecated and are superceded by new,
 uniquely named interfaces. The original Configs extend the new
 uniquely named interfaces. Subclassing these work as before and the
 existing rule signatures accept any previously implemented Config
 implementations. However, this is a breaking change if a user stored
 an instance of the <code class="language-plaintext highlighter-rouge">DEFAULT</code> object using the Config class name (as
 the <code class="language-plaintext highlighter-rouge">DEFAULT</code> instance now only implements the uniquely named
 interface).</li>
   <li>The <code class="language-plaintext highlighter-rouge">RelRule.Config.as()</code> method should only be used for safe
 downcasts. Before, it could do arbitrary casts. The exception is
 that arbitrary <code class="language-plaintext highlighter-rouge">as()</code> will continue to work when using the
 deprecated <code class="language-plaintext highlighter-rouge">RelRule.Config.EMPTY</code> field. In most cases, this should
 be a non-breaking change. However, all Calcite-defined <code class="language-plaintext highlighter-rouge">DEFAULT</code>
 rule config instances use Immutables. As such, if one had previously
 subclassed a <code class="language-plaintext highlighter-rouge">RelRule.Config</code> subclass and then used the <code class="language-plaintext highlighter-rouge">DEFAULT</code>
 instance from that subclass, the <code class="language-plaintext highlighter-rouge">as()</code> call will no longer work to
 coerce the <code class="language-plaintext highlighter-rouge">DEFAULT</code> instance into a arbitrary subclass. In essence,
 outside the <code class="language-plaintext highlighter-rouge">EMPTY</code> use, <code class="language-plaintext highlighter-rouge">as()</code> is now only safe to do if a Java
 cast is also safe.</li>
   <li>
 <code class="language-plaintext highlighter-rouge">ExchangeRemoveConstantKeysRule.Config</code> and
 <code class="language-plaintext highlighter-rouge">ValuesReduceRule.Config</code> now declare concrete bounds for their
 matchHandler configuration. This is a breaking change if one did not
 use the Rule as a bounding variable.</li>
   <li>Collections used in Immutables value classes will be converted to
 Immutable collection types even if the passed in parameter is
 mutable (such as an <code class="language-plaintext highlighter-rouge">ArrayList</code>). As such, consumers of those
 configuration properties cannot mutate the returned collections.</li>
 </ul>


     <p>See the <a href="/docs/history.html#v1-28-0">release notes</a>;
       <a href="/downloads#source-releases">download</a> the release.</p>

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	<option value="/news/2015/09/02/release-1.4.0-incubating/">Release 1.4.0 Incubating</option>
	<option value="/news/2015/07/31/xldb-best-lightning-talk/">XLDB 2015 best lightning talk</option>
	<option value="/news/2015/06/05/algebra-builder/">Algebra builder</option>
	<option value="/news/2015/05/30/release-1.3.0-incubating/">Release 1.3.0 Incubating</option>
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	<h2>
	Release 1.28.0
	<a href="/news/2021/10/19/release-1.28.0/" class="permalink" title="Permalink">∞</a>
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	release
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	19 Oct 2021
	</span>



	<a href="http://people.apache.org/~jhyde" class="post-author">
	<img src="https://github.com/julianhyde.png" class="avatar" alt="jhyde avatar" width="24" height="24">
	jhyde
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	<!--

	-->

	<p>The <a href="">Apache Calcite PMC</a>
	is pleased to announce
	<a href="/docs/history.html#v1-28-0">Apache Calcite release 1.28.0</a>.</p>

	<p>This release comes four months after <a href="/docs/history.html#v1-27-0">1.27.0</a>,
	contains contributions from 38 authors,
	and resolves 76 issues.
	New features include the
	<a href="https://issues.apache.org/jira/browse/CALCITE-4486">UNIQUE</a>
	sub-query predicate, the
	<a href="https://issues.apache.org/jira/browse/CALCITE-4661">MODE</a> aggregate function,
	<a href="https://issues.apache.org/jira/browse/CALCITE-4644">PERCENTILE_CONT and PERCENTILE_DISC</a>
	inverse distribution functions, an
	<a href="https://issues.apache.org/jira/browse/CALCITE-4614">Exasol dialect</a>
	for the JDBC adapter, and improvements to
	<a href="https://issues.apache.org/jira/browse/CALCITE-4779">materialized</a>
	<a href="https://issues.apache.org/jira/browse/CALCITE-3935">view</a>
	<a href="https://issues.apache.org/jira/browse/CALCITE-4774">recognition</a>.</p>

	<p>This release contains some breaking changes (described below) due to the
	<a href="https://issues.apache.org/jira/browse/CALCITE-4787">replacement of ImmutableBeans with Immutables</a>.
	Two APIs are deprecated and will be
	<a href="/docs/history.html#to-be-removed-in-1-29-0">removed in release 1.29</a>.</p>

	<h2 id="breaking-changes-to-immutablebeans">Breaking changes to ImmutableBeans</h2>

	<p>In 1.28, Calcite converted the recently introduced
	<a href="https://issues.apache.org/jira/browse/CALCITE-3328">configuration system</a>
	from an internal system based on
	<a href="https://github.com/apache/calcite/blob/main/core/src/main/java/org/apache/calcite/util/ImmutableBeans.java">ImmutableBeans</a>
	to instead use the <a href="https://immutables.github.io/">Immutables</a>
	annotation processor. This library brings a large number of additional
	features that should make value-type classes in Calcite easier to
	build and leverage. It also reduces reliance on dynamic proxies, which
	should improve performance and reduce memory footprint. Lastly, this
	change increases compatibility with ahead-of-time compilation
	technologies such as <a href="https://www.graalvm.org/">GraalVM</a>. As part of
	this change, a number of minor changes have been made and key methods
	and classes have been deprecated. The change was designed to minimize
	disruption to existing consumers of Calcite but the following minor
	changes needed to be made:</p>
	<ul>
	<li>The
	<a href="https://github.com/apache/calcite/blob/main/core/src/main/java/org/apache/calcite/plan/RelRule.java#L125">RelRule.Config.EMPTY</a>
	field is now deprecated. To create a new configuration subclass, you
	can either use your preferred interface-implementation based
	construction or you can leverage Immutables. To do the latter,
	<a href="https://immutables.github.io/getstarted.html">configure your project</a>
	to use the Immutables annotation processor and annotate your
	subclass with the
	<a href="https://immutables.github.io/immutable.html#value"><code class="language-plaintext highlighter-rouge">@Value.Immutable</code></a>
	annotation.</li>
	<li>Where <code class="language-plaintext highlighter-rouge">RelRule.Config</code> subclasses were nested 2+ classes deep, the
	interfaces have been marked deprecated and are superceded by new,
	uniquely named interfaces. The original Configs extend the new
	uniquely named interfaces. Subclassing these work as before and the
	existing rule signatures accept any previously implemented Config
	implementations. However, this is a breaking change if a user stored
	an instance of the <code class="language-plaintext highlighter-rouge">DEFAULT</code> object using the Config class name (as
	the <code class="language-plaintext highlighter-rouge">DEFAULT</code> instance now only implements the uniquely named
	interface).</li>
	<li>The <code class="language-plaintext highlighter-rouge">RelRule.Config.as()</code> method should only be used for safe
	downcasts. Before, it could do arbitrary casts. The exception is
	that arbitrary <code class="language-plaintext highlighter-rouge">as()</code> will continue to work when using the
	deprecated <code class="language-plaintext highlighter-rouge">RelRule.Config.EMPTY</code> field. In most cases, this should
	be a non-breaking change. However, all Calcite-defined <code class="language-plaintext highlighter-rouge">DEFAULT</code>
	rule config instances use Immutables. As such, if one had previously
	subclassed a <code class="language-plaintext highlighter-rouge">RelRule.Config</code> subclass and then used the <code class="language-plaintext highlighter-rouge">DEFAULT</code>
	instance from that subclass, the <code class="language-plaintext highlighter-rouge">as()</code> call will no longer work to
	coerce the <code class="language-plaintext highlighter-rouge">DEFAULT</code> instance into a arbitrary subclass. In essence,
	outside the <code class="language-plaintext highlighter-rouge">EMPTY</code> use, <code class="language-plaintext highlighter-rouge">as()</code> is now only safe to do if a Java
	cast is also safe.</li>
	<li>
	<code class="language-plaintext highlighter-rouge">ExchangeRemoveConstantKeysRule.Config</code> and
	<code class="language-plaintext highlighter-rouge">ValuesReduceRule.Config</code> now declare concrete bounds for their
	matchHandler configuration. This is a breaking change if one did not
	use the Rule as a bounding variable.</li>
	<li>Collections used in Immutables value classes will be converted to
	Immutable collection types even if the passed in parameter is
	mutable (such as an <code class="language-plaintext highlighter-rouge">ArrayList</code>). As such, consumers of those
	configuration properties cannot mutate the returned collections.</li>
	</ul>


	<p>See the <a href="/docs/history.html#v1-28-0">release notes</a>;
	<a href="/downloads#source-releases">download</a> the release.</p>

	</div>
	</article>

	</div>

	<div class="unit one-fifth hide-on-mobiles">
	<aside>
	<ul>
	<li class="">
	<a href="/news/">All News</a>
	</li>
	<li class="">
	<a href="/news/releases/">Calcite Releases</a>
	</li>
	</ul>
	<h4>Recent Releases</h4>
	<ul>

	<li class="">
	<a href="/news/2023/02/07/release_1.33.0/">1.33.0</a>
	</li>

	<li class="">
	<a href="/news/2022/09/10/release-1.32.0/">1.32.0</a>
	</li>

	<li class="">
	<a href="/news/2022/08/02/release-1.31.0/">1.31.0</a>
	</li>

	<li class="">
	<a href="/news/2022/03/19/release-1.30.0/">1.30.0</a>
	</li>

	<li class="">
	<a href="/news/2021/12/25/release-1.29.0/">1.29.0</a>
	</li>

	</ul>
	<h4>Other News</h4>
	<ul>

	<li class="">
	<a href="/news/2021/01/11/meetup/">Calcite Online Meetup January 2021</a>
	</li>

	<li class="">
	<a href="/news/2017/03/31/new-avatica-repository/">New Avatica Repository</a>
	</li>

	<li class="">
	<a href="/news/2016/03/22/cassandra-adapter/">Cassandra Adapter</a>
	</li>

	<li class="">
	<a href="/news/2016/02/17/streaming-sql-talk/">Streaming SQL in Samza</a>
	</li>

	<li class="">
	<a href="/news/2016/02/17/elser-pmc/">Calcite appoints Josh Elser to PMC</a>
	</li>

	<li class="">
	<a href="/news/2015/11/08/new-committers/">Calcite adds 2 committers</a>
	</li>

	<li class="">
	<a href="/news/2015/10/22/calcite-graduates/">Calcite Graduates</a>
	</li>

	<li class="">
	<a href="/news/2015/07/31/xldb-best-lightning-talk/">XLDB 2015 best lightning talk</a>
	</li>

	<li class="">
	<a href="/news/2015/06/05/algebra-builder/">Algebra builder</a>
	</li>

	<li class="">
	<a href="/news/2015/04/24/new-committers/">Calcite adds 5 committers</a>
	</li>

	</ul>
	</aside>
	</div>


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