On the Definition of Service Granularity and Its Architectural Impact

Service granularity generally refers to the size of a service. The fact that services should be large-sized or coarse-grained is often postulated as a fundamental design principle of Service Oriented Architecture (SOA). However, multiple meanings are put on the term granularity and the impact of granularity on architectural qualities is not always clear. In order to structure the discussion, the authors propose a classification of service granularity types that reflect three different interpretations. Firstly, functionality granularity refers to how much functionality is offered by a service. Secondly, data granularity reflects the amount of data that are exchanged with a service. Finally, the business value granularity of a service indicates to which extent the service provides added business value.