Updating Hive Targets with an Update Strategy Transformation
Updating Hive Targets with an Update Strategy Transformation
For mappings that run on the Spark engine, you can use Hive MERGE statements to perform Update Strategy tasks. When a query uses a MERGE statement instead of INSERT, UPDATE or DELETE statements, processing is more efficient.
To use Hive MERGE, select
true
for the option in the Advanced Properties of the Update Strategy transformation.
The mapping ignores the Hive MERGE option and the Data Integration Service uses INSERT, UPDATE and DELETE to perform the operation under the following scenarios:
The mapping runs on the Blaze engine.
Hive MERGE is restricted on the Hadoop distribution.
The mapping log contains results of the operation, including whether restrictions affected results.
When the update affects partitioning or bucketing columns, updates to the columns are omitted.
The Developer tool and the Data Integration Service do not validate against this restriction. If the Update Strategy expression violates these restrictions, the mapping might produce unexpected results.