docs/topics/impala_disable_codegen.xml

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

  <title>DISABLE_CODEGEN Query Option</title>
  <titlealts audience="PDF"><navtitle>DISABLE_CODEGEN</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>
      <indexterm audience="hidden">DISABLE_CODEGEN query option</indexterm>
      This is a debug option, intended for diagnosing and working around issues that cause crashes. If a query
      fails with an <q>illegal instruction</q> or other hardware-specific message, try setting
      <codeph>DISABLE_CODEGEN=true</codeph> and running the query again. If the query succeeds only when the
      <codeph>DISABLE_CODEGEN</codeph> option is turned on, submit the problem to <keyword keyref="support_org"/> and include that
      detail in the problem report. Do not otherwise run with this setting turned on, because it results in lower
      overall performance.
    </p>

    <p>
      Because the code generation phase adds a small amount of overhead for each query, you might turn on the
      <codeph>DISABLE_CODEGEN</codeph> option to achieve maximum throughput when running many short-lived queries
      against small tables.
    </p>

    <p conref="../shared/impala_common.xml#common/type_boolean"/>
    <p conref="../shared/impala_common.xml#common/default_false_0"/>

  </conbody>
</concept>