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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="batch_size">
<title>BATCH_SIZE Query Option</title>
<titlealts audience="PDF"><navtitle>BATCH SIZE</navtitle></titlealts>
<prolog>
<metadata>
<data name="Category" value="Impala"/>
<data name="Category" value="Impala Query Options"/>
<data name="Category" value="Developers"/>
<data name="Category" value="Data Analysts"/>
<data name="Category" value="Querying"/>
<data name="Category" value="Performance"/>
</metadata>
</prolog>
<conbody>
<p>
<indexterm audience="hidden">BATCH_SIZE query option</indexterm>
Number of rows evaluated at a time by SQL operators. Unspecified or a size of 0 uses a predefined default
size. Using a large number improves responsiveness, especially for scan operations, at the cost of a higher memory footprint.
</p>
<p>
This option is primarily for testing during Impala development, or for use under the direction of <keyword keyref="support_org"/>.
</p>
<p>
<b>Type:</b> numeric
</p>
<p>
<b>Default:</b> 0 (meaning the predefined default of 1024)
</p>
<p rev="2.11.0 IMPALA-5541">
<b>Range:</b> 0-65536. The value of 0 still has the special meaning of <q>use the default</q>,
so the effective range is 1-65536. The maximum applies in <keyword keyref="impala211_full"/> and higher.
</p>
</conbody>
</concept>