I was in favor of doubling the complexity by prefixing RDB with event logs, for retrospective QA/analysis and prospective client segregation. Databases now are

I was in favor of doubling the complexity by prefixing RDB with event logs, for retrospective QA/analysis and prospective client segregation. Databases now are a snapshot of the data modeling and usage at a particular point in application lifecycle. We manage to migrate data as it evolves, but you can't go back in time. Why go back? In our case, our interpretation of events (as we stuffed data into the DB) was hiding the data we actually needed to discover problems with our (bioinformatics and factory) workflow - the difference between expected and actual output that results from e.g., bad batches of reagent or a broken picker tip. We only stored e.g., the expected blend of reagents because that's all we needed for planning. That meant we had no way to recover the actions leading to that blend for purposes of retrospective quality analysis. So my proposal was to log all actions, derive models (of plate state) as usual for purpose of present applications, but still be able to run data analysis on the log to do QA when results were problematic. Ha ha! They said, but still :) Event prefixing might also help in the now/later design trade-off. Typically we design around requirements now, and make some accommodation for later if it's not too costly. Using an event log up front might work for future-proofing. It also permits "incompatible" schema to co-exist for different clients, as legacy applications read the legacy downstream DB, while new ones read the upcoming DB. For a bio service provider, old clients validate a given version, and they don't want the new model or software, while new clients want the new stuff you're building for them. You end up maintaining different DB models and infrastructure -- yuck! But with event sourcing, you can at least isolate the deltas, so e.g., HIPAA controls and auditing live in the event layer, and don't apply to the in-memory bits. TBH, a pitch like Rama's would play better in concert with existing DB's, to incrementally migrate the workflows that would benefit from it. Managers are often happy to let IT entrepreneurs experiment if it keeps them happy and away from messing with business-critical functions. YMMV...