mirror of
https://github.com/apache/impala.git
synced 2026-01-10 09:00:16 -05:00
eadd35f6d5
The recent documentation formatting changes introduced the navigation panel on the left. However, due to the length of the query options navigation title these could overlap with the documentation paragraphs. This commit removes the underscores from the navigation titles of the query options, so browsers can break them into multiple lines. Additionally, the "SET" and "Query Options for the SET Statement" pages are merged to save some more space for the query option navigation titles. Testing: - Built the documentation and tested manually Change-Id: Icec787d7a2af848aaaff65be2ecf311a5ce8fe7f Reviewed-on: http://gerrit.cloudera.org:8080/20556 Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com> Reviewed-by: Jason Fehr <jfehr@cloudera.com> Reviewed-by: Peter Rozsa <prozsa@cloudera.com> Reviewed-by: Tamas Mate <tmater@apache.org>
87 lines
2.4 KiB
XML
87 lines
2.4 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
|
|
<!--
|
|
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.
|
|
-->
|
|
<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
|
|
<concept id="enable_expr_rewrites">
|
|
|
|
<title>ENABLE_EXPR_REWRITES Query Option</title>
|
|
|
|
<titlealts audience="PDF">
|
|
|
|
<navtitle>ENABLE EXPR REWRITES</navtitle>
|
|
|
|
</titlealts>
|
|
|
|
<prolog>
|
|
<metadata>
|
|
<data name="Category" value="Impala"/>
|
|
<data name="Category" value="Impala Query Options"/>
|
|
<data name="Category" value="Troubleshooting"/>
|
|
<data name="Category" value="Performance"/>
|
|
</metadata>
|
|
</prolog>
|
|
|
|
<conbody>
|
|
|
|
<p>
|
|
The <codeph>ENABLE_EXPR_REWRITES</codeph> query option controls whether to enable or
|
|
disable the query compile time optimizations. These optimizations rewrite the expression
|
|
trees to a more compact and optimized form that helps avoid redundant expression
|
|
evaluation at run time. Performance optimizations controlled by this query option include:
|
|
</p>
|
|
|
|
<ul>
|
|
<li>
|
|
Constant folding (added in <keyword keyref="impala28">)</keyword>
|
|
</li>
|
|
|
|
<li>
|
|
Extracting common conjuncts from disjunctions (added in
|
|
<keyword
|
|
keyref="impala28">)</keyword>
|
|
</li>
|
|
|
|
<li>
|
|
Simplify conditionals with constant conditions (added in
|
|
<keyword
|
|
keyref="impala29">)</keyword>
|
|
</li>
|
|
</ul>
|
|
|
|
<p>
|
|
Set the option to <codeph>false</codeph> or <codeph>0</codeph> to disable the performance
|
|
optimizations.
|
|
</p>
|
|
|
|
<p>
|
|
<b>Type: </b><codeph>boolean</codeph>
|
|
</p>
|
|
|
|
<p>
|
|
<b>Default:</b> <codeph>true</codeph> (<codeph>1</codeph>)
|
|
</p>
|
|
|
|
<p>
|
|
<b>Added in:</b> <keyword keyref="impala28"/>
|
|
</p>
|
|
|
|
</conbody>
|
|
|
|
</concept>
|