docs/topics/impala_batch_size.xml

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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>