Native support of multi-tenancy in RDBMS for software as a service

Software as a Service (SaaS) facilitates acquiring a huge number of small tenants by providing low service fees. To achieve low service fees, it is essential to reduce costs per tenant. For this, consolidating multiple tenants onto a single relational schema instance turned out beneficial because of low overheads per tenant and scalable manageability. This approach implements data isolation between tenants, per-tenant schema extension and further tenant-centric data management features in application logic. This is complex, disables some optimization opportunities in the RDBMS and represents a conceptual misstep with Separation of Concerns in mind. Therefore, we contribute first features of a RDBMS to support tenant-aware data management natively. We introduce tenants as first-class database objects and propose the concept of a tenant context to isolate a tenant from other tenants. We present a schema inheritance concept that allows sharing a core application schema among tenants while enabling schema extensions per tenant. Finally, we evaluate a preliminary implementation of our approach.