Enabling Retroactive Computing Through Event Sourcing

by Michael Müller

Event sourcing is a style of software architecture wherein state altering operations to an application are captured as immutable events. Each event is appended to an event log, with the current state of a system derived from this series of events. This thesis addresses the utilization of retroactive capabilities in event-sourced systems: computing alternate application states, post hoc bug fixes, or the support of algorithms which have access to their own history, for example. The possibility of retroactively accessing and modifying this event log is a potential capability of an event-sourced system, but a detailed exploration how these operations can be facilitated and supported has not yet been conducted.
We examine how retroaction can be applied to event-sourced systems and discuss conceptual considerations. Furthermore, we demonstrate how different architectures can be used to provide retroaction and describe the prototypical implementation of an appropriate programming model. These findings are applied in the Chronograph research project, in order to utilize potential temporal aspects of this platform.

87 pages, ebook

First published March 31, 2016

About the author

Father Michael Mueller, C.SS.R., was born in 1825 in Germany. He later joined the Congregation of the Most Holy Redeemer, and was one of eleven clerics sent to the United States by the American Redemptorist Provincial. Upon completion of his theology studies in Maryland, he was ordained in 1853 by John Nepomucene Neumann. He served the Redemptorist communities in the U.S. as Consulter to the Provincial, as well as Superior and Novice Master. Father Mueller is the author of The Blessed Eucharist, Prayer: The Key to Salvation, Triumph of the Blessed Sacrament, The Prodigal Son, and God the Teacher of Mankind. He died in 1899.

Reviews

[Marko Kunic · Rating 5 out of 5]

I really enjoyed reading this. This thesis explains how to enhance ES with retroactive computing. I am not sure I will have a chance to use this, but I would still suggest people to read it.