Relational sources are valid in mappings that run in a Hadoop environment if you use the Hive engine or the Blaze engine. The Spark engine cannot run mappings with relational resources.
The Data Integration Service does not run pre-mapping SQL commands or post-mapping SQL commands against relational sources. You cannot validate and run a mapping with PreSQL or PostSQL properties for a relational source in a Hadoop environment.
The Data Integration Service can use multiple partitions to read from the following relational sources:
You do not have to set maximum parallelism for the Data Integration Service to use multiple partitions in the Hadoop environment.