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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> |