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<h2><a href="https://docs.jboss.org/author/display/TEIID/Cloudera+Impala+Translator">Cloudera Impala Translator</a></h2>
<h4>Page <b>added</b> by <a href="https://docs.jboss.org/author/display/~van.halbert">Van Halbert</a>
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<h1><a name="ClouderaImpalaTranslator-ClouderaImpalaTranslator%28impala%29"></a><b>Cloudera Impala Translator</b> (impala)</h1>
<p>The Coudera Impala Translator, known by the name of <b><em>impala</em></b>, is for use with Cloudera Impala 1.2.1 or later.</p>
<p>Impala has limited support for data types. It is does not have native support for time/date/xml or LOBs. These limitations are reflected in the translator capabilities. A Teiid view can use these types, however the transformation would need to specify the necessary conversions. Note that in those situations, the evaluations will be done in Teiid engine.</p>
<p>Impala only supports EQUI join, so using any other joins types on its source tables will result in inefficient queries.</p>
<p>To write criteria based on partitioned columns, modeled them on source table, but do not include them in selection columns.</p>
<div class='panelMacro'><table class='noteMacro'><colgroup><col width='24'><col></colgroup><tr><td valign='top'><img src="/author/images/icons/emoticons/warning.gif" width="16" height="16" align="absmiddle" alt="" border="0"></td><td>Impala Hive importer does not have concept of catalog or source schema, nor does it import keys, procedures, indexes, etc.</td></tr></table></div>
<p>Impala specific importer properties:<br/>
*<em>useDatabaseMetaData</em>- Set to true to use the normal import logic with the option to import index information disabled. Defaults to false. </p>
<div class='panelMacro'><table class='noteMacro'><colgroup><col width='24'><col></colgroup><tr><td valign='top'><img src="/author/images/icons/emoticons/warning.gif" width="16" height="16" align="absmiddle" alt="" border="0"></td><td>If false the typical JDBC DatabaseMetaData calls are not used so not all of the common JDBC importer properties are applicable to Impala. You may still use excludeTables regardless.</td></tr></table></div>
<div class='panelMacro'><table class='noteMacro'><colgroup><col width='24'><col></colgroup><tr><td valign='top'><img src="/author/images/icons/emoticons/warning.gif" width="16" height="16" align="absmiddle" alt="" border="0"></td><td>Some versions of Impala requires the use of a LIMIT when performing an ORDER BY. If no default is configured in Impala, then an exception can occur when a Teiid query with an ORDER BY but no LIMIT is issued. You should set an Impala wide default, or configure the connection pool to use a new connection sql string to issue a SET DEFAULT_ORDER_BY_LIMIT statement. See the <a href="http://www.cloudera.com/content/cloudera-content/cloudera-docs/Impala/latest/Installing-and-Using-Impala/ciiu_langref_sql.html?scroll=limit_unique_1" class="external-link" rel="nofollow">Cloudera docs</a> for more on limit options - such as controlling what happens when the limit is exceeded.</td></tr></table></div>
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