High-scale interactive services demand high throughput with low latency and high availability, difficult goals to meet with a traditional stateless 3-tier architecture. The actor model makes it natural to build a stateful middle tier that achieves the required performance. However, most popular actor frameworks still pass many distributed system and database problems to application developers.

We present solutions to these problems that are integrated into the Orleans programming framework. Orleans introduced the virtual-actor abstraction, which liberates developers from dealing with many reliability and distributed resource management problems. Other advanced features of Orleans are streams, transactions, geo-distribution and indexing. Orleans’ lightweight and dynamic virtual-stream abstraction enables actors to receive events from stream sources via transport plug-ins. The distributed transaction abstraction supports the grouping of operations on multiple actors into an ACID transaction. Geo-distribution allows actors to be globally single-instanced, replicated, and invoked across many datacenters. Indexing enables the actors within a class to be selected based on values of properties of the actor. We will describe the programming model for each of these abstractions and aspects of their implementation.

Philip A. Bernstein is a Distinguished Scientist at Microsoft Research. Over the past 40 years, he has been a product architect at Microsoft and Digital Equipment Corp., a professor at Harvard University and Wang Institute of Graduate Studies, and a VP Software at Sequoia Systems. He has published over 150 papers and two books on the theory and implementation of database systems, especially on transaction processing and data integration, and has contributed to a variety of database products. He is a Fellow of the ACM and AAAS, a winner of ACM SIGMOD’s E.F. Codd Innovations Award, and a member of the Washington State Academy of Sciences and the National Academy of Engineering. He received a B.S. degree from Cornell and M.Sc. and Ph.D. from University of Toronto.