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Change-Id: I7a83aa42e6fffc7cb71112936129a0f1917ec2fd Reviewed-on: http://gerrit.cloudera.org:8080/10043 Reviewed-by: Tim Armstrong <tarmstrong@cloudera.com> Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
94 lines
3.3 KiB
XML
94 lines
3.3 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!--
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Licensed to the Apache Software Foundation (ASF) under one
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or more contributor license agreements. See the NOTICE file
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distributed with this work for additional information
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regarding copyright ownership. The ASF licenses this file
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to you under the Apache License, Version 2.0 (the
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"License"); you may not use this file except in compliance
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with the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing,
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software distributed under the License is distributed on an
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"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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KIND, either express or implied. See the License for the
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specific language governing permissions and limitations
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under the License.
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-->
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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
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<concept rev="2.12.0" id="exec_time_limit_s">
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<title>EXEC_TIME_LIMIT_S Query Option (<keyword keyref="impala212_full"/> or higher only)</title>
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<titlealts audience="PDF">
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<navtitle>EXEC_TIME_LIMIT_S</navtitle>
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</titlealts>
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<prolog>
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<metadata>
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<data name="Category" value="Impala"/>
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<data name="Category" value="Impala Query Options"/>
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<data name="Category" value="Querying"/>
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<data name="Category" value="Developers"/>
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<data name="Category" value="Data Analysts"/>
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</metadata>
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</prolog>
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<conbody>
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<p rev="2.12.0">
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The <codeph>EXEC_TIME_LIMIT_S</codeph> query option sets a time limit on query execution.
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If a query is still executing when time limit expires, it is automatically canceled. The
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option is intended to prevent runaway queries that execute for much longer than intended.
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</p>
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<p>
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For example, an Impala administrator could set a default value of
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<codeph>EXEC_TIME_LIMIT_S=3600</codeph> for a resource pool to automatically kill queries
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that execute for longer than one hour (see
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<xref href="impala_admission.xml#admission_control"/> for information about default query
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options). Then, if a user accidentally runs a large query that executes for more than one
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hour, it will be automatically killed after the time limit expires to free up resources.
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Users can override the default value per query or per session if they do not want the
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default <codeph>EXEC_TIME_LIMIT_S</codeph> value to apply to a specific query or a
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session.
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</p>
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<note>
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<p>
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The time limit only starts once the query is executing. Time spent planning the query,
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scheduling the query, or in admission control is not counted towards the execution time
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limit. <codeph>SELECT</codeph> statements are eligible for automatic cancellation until
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the client has fetched all result rows. DML queries are eligible for automatic
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cancellation until the DML statement has finished.
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</p>
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</note>
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<p conref="../shared/impala_common.xml#common/syntax_blurb"/>
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<codeblock>SET EXEC_TIME_LIMIT_S=<varname>seconds</varname>;</codeblock>
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<p>
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<b>Type:</b> numeric
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</p>
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<p>
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<b>Default:</b> 0 (no time limit )
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</p>
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<p conref="../shared/impala_common.xml#common/added_in_212"/>
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<p conref="../shared/impala_common.xml#common/related_info"/>
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<p>
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<xref href="impala_timeouts.xml#timeouts"/>
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</p>
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</conbody>
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</concept>
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