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Posted to commits@impala.apache.org by jo...@apache.org on 2020/03/17 23:05:10 UTC
[impala] branch master updated: IMPALA-9517: [DOCS] Document
broadcast_bytes_limit query option
This is an automated email from the ASF dual-hosted git repository.
joemcdonnell pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/impala.git
The following commit(s) were added to refs/heads/master by this push:
new 15f0ea9 IMPALA-9517: [DOCS] Document broadcast_bytes_limit query option
15f0ea9 is described below
commit 15f0ea9476ea9236c0e038c603a4bc63ba1f4b7a
Author: Kris Hahn <kh...@cloudera.com>
AuthorDate: Mon Mar 16 21:15:36 2020 -0700
IMPALA-9517: [DOCS] Document broadcast_bytes_limit query option
- Minor edit
Change-Id: I2f7eaacd5a885a7a5292d7694241d58e4f7b6282
(cherry picked from commit 0f1c87f814b5af4f6b37c5ebf095e887916424ef)
Reviewed-on: http://gerrit.cloudera.org:8080/15457
Tested-by: Impala Public Jenkins <im...@cloudera.com>
Reviewed-by: Aman Sinha <am...@cloudera.com>
Reviewed-by: Joe McDonnell <jo...@cloudera.com>
---
docs/impala.ditamap | 1 +
docs/topics/impala_broadcast_bytes_limit.xml | 67 ++++++++++++++++++++++++++++
2 files changed, 68 insertions(+)
diff --git a/docs/impala.ditamap b/docs/impala.ditamap
index b1d8e85..c5b3191 100644
--- a/docs/impala.ditamap
+++ b/docs/impala.ditamap
@@ -174,6 +174,7 @@ under the License.
<topicref href="topics/impala_allow_unsupported_formats.xml"/>
<topicref href="topics/impala_appx_count_distinct.xml"/>
<topicref href="topics/impala_batch_size.xml"/>
+ <topicref href="topics/impala_broadcast_bytes_limit.xml"/>
<topicref rev="2.10.0 IMPALA-3200" href="topics/impala_buffer_pool_limit.xml"/>
<topicref href="topics/impala_compression_codec.xml"/>
<topicref href="topics/impala_compute_stats_min_sample_size.xml"/>
diff --git a/docs/topics/impala_broadcast_bytes_limit.xml b/docs/topics/impala_broadcast_bytes_limit.xml
new file mode 100644
index 0000000..283cd9c
--- /dev/null
+++ b/docs/topics/impala_broadcast_bytes_limit.xml
@@ -0,0 +1,67 @@
+<?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="broadcast_bytes_limit">
+
+ <title>BROADCAST_BYTES_LIMIT Query Option</title>
+
+ <titlealts audience="PDF">
+
+ <navtitle>BROADCAST_BYTES_LIMIT</navtitle>
+
+ </titlealts>
+
+ <prolog>
+ <metadata>
+ <data name="Category" value="Impala"/>
+ <data name="Category" value="Impala Query Options"/>
+ </metadata>
+ </prolog>
+
+ <conbody>
+
+ <p>
+ <indexterm audience="hidden">BROADCAST_BYTES_LIMIT query option</indexterm> Sets the limit
+ for the size of the broadcast input based on estimated size.
+ </p>
+ <p>
+ The Impala planner may in rare cases make a bad choice to broadcast a large table or intermediate
+ result and encounter performance problems due to high memory pressure. Setting this limit will
+ make the planner pick a partition based hash join instead of broadcast and avoid such performance problems.
+ </p>
+ <p conref="../shared/impala_common.xml#common/type_integer"/>
+
+ <p conref="../shared/impala_common.xml#common/default_blurb"/>
+
+ <p>
+ The default value is 34359738368 (32 GB). A value of 0 causes the option to be ignored.
+ </p>
+ <p conref="../shared/impala_common.xml#common/example_blurb"/>
+
+<codeblock><![CDATA[
+-- Change the limit to 16GB.
+set broadcast_bytes_limit=17179869184;
+
+-- Disable the BROADCAST_BYTES_LIMIT.
+set broadcast_bytes_limit=0;
+]]>
+</codeblock>
+ </conbody>
+</concept>