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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="parquet_annotate_strings_utf8" rev="2.6.0 IMPALA-2069">
<title>PARQUET_ANNOTATE_STRINGS_UTF8 Query Option (<keyword keyref="impala26"/> or higher only)</title>
<titlealts audience="PDF"><navtitle>PARQUET_ANNOTATE_STRINGS_UTF8</navtitle></titlealts>
<data name="Category" value="Impala"/>
<data name="Category" value="Impala Query Options"/>
<data name="Category" value="Parquet"/>
<data name="Category" value="Developers"/>
<data name="Category" value="Data Analysts"/>
<p rev="2.6.0 IMPALA-2069">
<indexterm audience="hidden">PARQUET_ANNOTATE_STRINGS_UTF8 query option</indexterm>
Causes Impala <codeph>INSERT</codeph> and <codeph>CREATE TABLE AS SELECT</codeph> statements
to write Parquet files that use the UTF-8 annotation for <codeph>STRING</codeph> columns.
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
By default, Impala represents a <codeph>STRING</codeph> column in Parquet as an unannotated binary field.
Impala always uses the UTF-8 annotation when writing <codeph>CHAR</codeph> and <codeph>VARCHAR</codeph>
columns to Parquet files. An alternative to using the query option is to cast <codeph>STRING</codeph>
values to <codeph>VARCHAR</codeph>.
This option is to help make Impala-written data more interoperable with other data processing engines.
Impala itself currently does not support all operations on UTF-8 data.
Although data processed by Impala is typically represented in ASCII, it is valid to designate the
data as UTF-8 when storing on disk, because ASCII is a subset of UTF-8.
<p conref="../shared/impala_common.xml#common/type_boolean"/>
<p conref="../shared/impala_common.xml#common/default_false_0"/>
<p conref="../shared/impala_common.xml#common/added_in_260"/>
<p conref="../shared/impala_common.xml#common/related_info"/>
<xref href="impala_parquet.xml#parquet"/>