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

  <title>Query Options for the SET Statement</title>
  <prolog>
    <metadata>
      <data name="Category" value="Impala Query Options"/>
      <data name="Category" value="Impala"/>
      <data name="Category" value="impala-shell"/>
      <data name="Category" value="SQL"/>
      <data name="Category" value="Querying"/>
      <data name="Category" value="Configuring"/>
      <data name="Category" value="Data Analysts"/>
      <data name="Category" value="Developers"/>
    </metadata>
  </prolog>

  <conbody>

    <p>
      You can specify the following options using the <codeph>SET</codeph> statement, and those settings affect all
      queries issued from that session.
    </p>

    <p>
      Some query options are useful in day-to-day operations for improving usability, performance, or flexibility.
    </p>

    <p>
      Other query options control special-purpose aspects of Impala operation and are intended primarily for
      advanced debugging or troubleshooting.
    </p>

    <p>
      Options with Boolean parameters can be set to 1 or <codeph>true</codeph> to enable, or 0 or <codeph>false</codeph>
      to turn off.
    </p>

    <note rev="2.0.0">
      <p rev="2.0.0">
        In Impala 2.0 and later, you can set query options directly through the JDBC and ODBC interfaces by using the
        <codeph>SET</codeph> statement. Formerly, <codeph>SET</codeph> was only available as a command within the
        <cmdname>impala-shell</cmdname> interpreter.
      </p>
      <p rev="2.11.0">
        In <keyword keyref="impala211_full"/> and later, you can set query options for an <cmdname>impala-shell</cmdname> session
        by specifying one or more command-line arguments of the form
        <codeph>--query_option=<varname>option</varname>=<varname>value</varname></codeph>.
        See <xref keyref="shell_options"/> for details.
      </p>
    </note>

<!-- This is the list including defaults from the pre-release 1.2 impala-shell:
        ABORT_ON_DEFAULT_LIMIT_EXCEEDED: 0
        ABORT_ON_ERROR: 0
        ALLOW_UNSUPPORTED_FORMATS: 0
        BATCH_SIZE: 0
        DEBUG_ACTION:
        DEFAULT_ORDER_BY_LIMIT: -1
        DISABLE_CODEGEN: 0
        HBASE_CACHE_BLOCKS: 0
        HBASE_CACHING: 0
        MAX_ERRORS: 0
        MAX_IO_BUFFERS: 0
        MAX_SCAN_RANGE_LENGTH: 0
        MEM_LIMIT: 0
        NUM_NODES: 0
        NUM_SCANNER_THREADS: 0
        PARQUET_COMPRESSION_CODEC: SNAPPY
        PARQUET_FILE_SIZE: 0
        SUPPORT_START_OVER: false
-->

    <p outputclass="toc"/>

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

    <p>
      <xref href="impala_set.xml#set"/>
    </p>
  </conbody>
</concept>