docs/topics/impala_exec_time_limit_s.xml

<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept rev="2.12.0" id="exec_time_limit_s">

  <title>EXEC_TIME_LIMIT_S Query Option (<keyword keyref="impala212_full"/> or higher only)</title>

  <titlealts audience="PDF">

    <navtitle>EXEC_TIME_LIMIT_S</navtitle>

  </titlealts>

  <prolog>
    <metadata>
      <data name="Category" value="Impala"/>
      <data name="Category" value="Impala Query Options"/>
      <data name="Category" value="Querying"/>
      <data name="Category" value="Developers"/>
      <data name="Category" value="Data Analysts"/>
    </metadata>
  </prolog>

  <conbody>

    <p rev="2.12.0">
      The <codeph>EXEC_TIME_LIMIT_S</codeph> query option sets a time limit on query execution.
      If a query is still executing when time limit expires, it is automatically canceled. The
      option is intended to prevent runaway queries that execute for much longer than intended.
    </p>

    <p>
      For example, an Impala administrator could set a default value of
      <codeph>EXEC_TIME_LIMIT_S=3600</codeph> for a resource pool to automatically kill queries
      that execute for longer than one hour (see
      <xref href="impala_admission.xml#admission_control"/> for information about default query
      options). Then, if a user accidentally runs a large query that executes for more than one
      hour, it will be automatically killed after the time limit expires to free up resources.
      Users can override the default value per query or per session if they do not want the
      default <codeph>EXEC_TIME_LIMIT_S</codeph> value to apply to a specific query or a
      session.
    </p>

    <note>
      <p>
        The time limit only starts once the query is executing. Time spent planning the query,
        scheduling the query, or in admission control is not counted towards the execution time
        limit. <codeph>SELECT</codeph> statements are eligible for automatic cancellation until
        the client has fetched all result rows. DML queries are eligible for automatic
        cancellation until the DML statement has finished.
      </p>
    </note>

    <p conref="../shared/impala_common.xml#common/syntax_blurb"/>

<codeblock>SET EXEC_TIME_LIMIT_S=<varname>seconds</varname>;</codeblock>

    <p>
      <b>Type:</b> numeric
    </p>

    <p>
      <b>Default:</b> 0 (no time limit )
    </p>

    <p conref="../shared/impala_common.xml#common/added_in_212"/>

    <p conref="../shared/impala_common.xml#common/related_info"/>

    <p>
      <xref href="impala_timeouts.xml#timeouts"/>
    </p>

  </conbody>

</concept>