Hi,
For prepare recipe you only have the choice between Streaming, Hadoop/Mapreduce or Spark.
You don't have SQL engine because we generate java code we can not push in a SQL db.
https://doc.dataiku.com/dss/latest/preparation/engines.html
For sync recipe, as the purpose is to move data from one system to another, in some case we have to stream the data.
Matt
Mattsco