pepijnve commented on code in PR #122:
URL: https://github.com/apache/datafusion-site/pull/122#discussion_r2640039685
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content/blog/2025-11-11-datafusion_case.md:
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@@ -0,0 +1,377 @@
+---
+layout: post
+title: Optimizing CASE Expression Evaluation
+date: 2025-11-11
+author: Pepijn Van Eeckhoudt
+categories: [features]
+---
+<!--
+{% comment %}
+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
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+{% endcomment %}
+-->
+
+[TOC]
+
+<style>
+figure {
+ margin: 20px 0;
+}
+
+figure img {
+ display: block;
+ max-width: 80%;
+ margin: auto;
+}
+
+figcaption {
+ font-style: italic;
+ color: #555;
+ font-size: 0.9em;
+ max-width: 80%;
+ margin: auto;
+ text-align: center;
+}
+</style>
+
+# Optimizing CASE Expression Evaluation in DataFusion
+
+SQL's `CASE` expression is one of the few constructs the language provides to
perform conditional logic.
+Its deceptively simple syntax hides significant implementation complexity.
+Over the past few weeks, we've landed a series of improvements to DataFusion's
`CASE` expression evaluator that reduce both CPU time and memory allocations.
Review Comment:
Text updated
##########
content/blog/2025-11-11-datafusion_case.md:
##########
@@ -0,0 +1,377 @@
+---
+layout: post
+title: Optimizing CASE Expression Evaluation
+date: 2025-11-11
+author: Pepijn Van Eeckhoudt
+categories: [features]
+---
+<!--
+{% comment %}
+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
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+{% endcomment %}
+-->
+
+[TOC]
+
+<style>
+figure {
+ margin: 20px 0;
+}
+
+figure img {
+ display: block;
+ max-width: 80%;
+ margin: auto;
+}
+
+figcaption {
+ font-style: italic;
+ color: #555;
+ font-size: 0.9em;
+ max-width: 80%;
+ margin: auto;
+ text-align: center;
+}
+</style>
+
+# Optimizing CASE Expression Evaluation in DataFusion
+
+SQL's `CASE` expression is one of the few constructs the language provides to
perform conditional logic.
+Its deceptively simple syntax hides significant implementation complexity.
+Over the past few weeks, we've landed a series of improvements to DataFusion's
`CASE` expression evaluator that reduce both CPU time and memory allocations.
+This post walks through the original implementation, its performance
bottlenecks, and how we addressed them step by step.
+Finally we'll also take a look at some future improvements to `CASE` that are
in the works.
+
+## Background: CASE Expression Evaluation
+
+SQL supports two forms of CASE expressions:
+
+1. **Simple**: `CASE expr WHEN value1 THEN result1 WHEN value2 THEN result2
... END`
+2. **Searched**: `CASE WHEN condition1 THEN result1 WHEN condition2 THEN
result2 ... END`
+
+The simple form evaluates an expression once for each input row and then tests
that value against the constants (or expressions) in each `WHEN` clause using
equality comparisons.
Review Comment:
Done
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