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Posted to commits@impala.apache.org by ta...@apache.org on 2018/08/23 20:59:00 UTC
[5/6] impala git commit: IMPALA-5937: [DOCS] Documented
ENABLE_EXPR_REWRITES query option
IMPALA-5937: [DOCS] Documented ENABLE_EXPR_REWRITES query option
Change-Id: I82a27172a6a6570f9c3cebe1a516a29c755e6d58
Reviewed-on: http://gerrit.cloudera.org:8080/11206
Tested-by: Impala Public Jenkins <im...@cloudera.com>
Reviewed-by: Thomas Marshall <th...@cmu.edu>
Project: http://git-wip-us.apache.org/repos/asf/impala/repo
Commit: http://git-wip-us.apache.org/repos/asf/impala/commit/d1d07f72
Tree: http://git-wip-us.apache.org/repos/asf/impala/tree/d1d07f72
Diff: http://git-wip-us.apache.org/repos/asf/impala/diff/d1d07f72
Branch: refs/heads/master
Commit: d1d07f7295ae4d6876097f0f86cb722da63f4caa
Parents: df18658
Author: Alex Rodoni <ar...@cloudera.com>
Authored: Mon Aug 13 17:27:26 2018 -0700
Committer: Alex Rodoni <ar...@cloudera.com>
Committed: Thu Aug 23 20:11:31 2018 +0000
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docs/impala.ditamap | 1 +
docs/topics/impala_enable_expr_rewrites.xml | 86 ++++++++++++++++++++++++
2 files changed, 87 insertions(+)
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http://git-wip-us.apache.org/repos/asf/impala/blob/d1d07f72/docs/impala.ditamap
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diff --git a/docs/impala.ditamap b/docs/impala.ditamap
index 9260a9b..73c5d23 100644
--- a/docs/impala.ditamap
+++ b/docs/impala.ditamap
@@ -187,6 +187,7 @@ under the License.
<topicref rev="2.5.0" href="topics/impala_disable_row_runtime_filtering.xml"/>
<topicref rev="2.5.0" href="topics/impala_disable_streaming_preaggregations.xml"/>
<topicref href="topics/impala_disable_unsafe_spills.xml"/>
+ <topicref href="topics/impala_enable_expr_rewrites.xml"/>
<topicref href="topics/impala_exec_single_node_rows_threshold.xml"/>
<topicref href="topics/impala_exec_time_limit_s.xml"/>
<topicref href="topics/impala_explain_level.xml"/>
http://git-wip-us.apache.org/repos/asf/impala/blob/d1d07f72/docs/topics/impala_enable_expr_rewrites.xml
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diff --git a/docs/topics/impala_enable_expr_rewrites.xml b/docs/topics/impala_enable_expr_rewrites.xml
new file mode 100644
index 0000000..b52914a
--- /dev/null
+++ b/docs/topics/impala_enable_expr_rewrites.xml
@@ -0,0 +1,86 @@
+<?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 that 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>