docs/topics/impala_timezone.xml

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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept rev="3.1.0" id="timezone">

  <title>TIMEZONE Query Option (<keyword keyref="impala31_full"/> or higher only)</title>

  <titlealts audience="PDF">

    <navtitle>TIMEZONE</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>
      The <codeph>TIMEZONE</codeph> query option defines the timezone used for conversions
      between UTC and the local time. If not set, Impala uses the system time zone where the
      Coordinator Impalad runs. As query options are not sent to the Coordinator immediately,
      the timezones are validated only when the query runs.
    </p>

    <p>
      Impala takes the timezone into a consideration in the following cases:
      <ul>
        <li>
          When calling the <codeph>NOW()</codeph> function
        </li>

        <li>
          When converting between Unix time and timestamp if the
          <codeph>use_local_tz_for_unix_timestamp_conversions</codeph> flag is
          <codeph>TRUE</codeph>
        </li>

        <li>
          When reading Parquet timestamps written by Hive if the
          <codeph>convert_legacy_hive_parquet_utc_timestamps</codeph> flag is
          <codeph>TRUE</codeph>
        </li>
      </ul>
    </p>

    <p>
      <b>Syntax:</b>
    </p>

<codeblock>SET TIMEZONE=<varname>time zone</varname></codeblock>

    <p>
      <varname>time zone</varname> can be a canonical code or a time zone name defined in
      <xref
        href="https://en.wikipedia.org/wiki/List_of_tz_database_time_zones"
        format="html" scope="external">IANA
      Time Zone Database</xref>. The value is case-sensitive.
    </p>

    <p>
      Leading/trailing quotes (') and double quotes (") are stripped.
    </p>

    <p>
      If <varname>time zone</varname> is an empty string, the time zone for the query is set to
      the default time zone of the Impalad Coordinator.
    </p>

    <p>
      If <varname>time zone</varname> is <codeph>NULL</codeph> or a space character, Impala
      returns an error when the query is executed.
    </p>

    <p>
      <b>Type:</b> String
    </p>

    <p>
      <b>Default:</b> The system time zone where the Coordinator Impalad runs
    </p>

    <p>
      <b>Examples:</b>
<codeblock>SET TIMEZONE=UTC;
SET TIMEZONE="Europe/Budapest";</codeblock>
    </p>

    <p>
      <b>Added in:</b> <keyword keyref="impala31"/>
    </p>

  </conbody>

</concept>