Large memories have become an affordable storage medium for databases involving hundreds of Gigabytes on multi-processor systems. In this short note, we review our research on building relational engines to exploit this major shift in hardware perspective. It illustrates that key design issues related to parallelism poses architectural problems at all levels of a system architecture and whose impact is not easily predictable. The sheer size/complexity of a relational DBMS and the sliding requirements of frontier applications are indicative that a substantial research agenda remains wide open.