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| <!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
| <concept rev="4.0 IMPALA-10091" id="refresh_updated_hms"> |
| |
| <title>REFRESH_UPDATED_HMS_PARTITIONS Query Option</title> |
| |
| <titlealts audience="PDF"> |
| |
| <navtitle>REFRESH UPDATED HMS PARTITIONS</navtitle> |
| |
| </titlealts> |
| |
| <prolog> |
| <metadata> |
| <data name="Category" value="Impala"/> |
| <data name="Category" value="Impala Query Options"/> |
| <data name="Category" value="Querying"/> |
| <data name="Category" value="Developers"/> |
| <data name="Category" value="Administrators"/> |
| </metadata> |
| </prolog> |
| |
| <conbody> |
| |
| <p> |
| As the name implies the query option <codeph>REFRESH_UPDATED_HMS_PARTITIONS</codeph> is used |
| to refresh any updated HMS partitions. |
| </p> |
| |
| <p>This option is disabled by default so that the performance is not compromised when refreshing a |
| table. However, for certain corner case scenarios refresh table command does not detect changed |
| partitions. In case of the default refresh, catalogd detects, adds any new partitions and removes |
| any partitions which are not present in HMS anymore. However, it does not update any partitions |
| that changed (eg. change of location). When this query option is enabled, the refresh table |
| command will detect certain changes to the partitions and update them accordingly. Currently, |
| catalogd will update the partitions if any of the following StorageDescriptor properties have |
| been modified. 1. Partition Location 2. Partition Fileformat. 3 SerdeInfo. 4. Partition schema |
| changes. 5. Partition bucketInfo.</p> |
| |
| <p> |
| <b>Type:</b><codeph>BOOLEAN</codeph>; recognized values are 1 and 0, or true and false; any other |
| value will be interpreted as false. |
| </p> |
| |
| <p> |
| <b>Default:</b><codeph>FALSE</codeph> (shown as 0 in output of SET statement). |
| </p> |
| |
| <p><b>Added in:</b> |
| <keyword keyref="impala40"/></p> |
| |
| </conbody> |
| |
| </concept> |