Do you have examples of micro services and good data warehouses working well side by side? Your point makes sense, but I keep hoping for a way to have One Data Source Truth working side by side with the services that across it.
I hate to burst your bubble, but you shouldn’t and can’t have truth working along side systems that access it. Data is messy and tends toward dishonesty. The only way to get clean truth for your organization is by thoughtfully applying rules, cleaning and filtering as you go. The more micro your architecture is, the more this is true. Because there is no way 20different teams are all going to have the same understanding of the business rules around what constitutes good, clean input data. Even if your company is very clear and well-documented about business and data rules, if you hand the same spec sheet to 20 different teams, you are going to get 20 variations on that spec.
The only way to get usable data that can be agreed upon by an entire company (or even business unit) is by separating your truth from your transactional data. That’s kind of the definitional of a data warehouse.
If you let your transactional systems access and update data directly in your warehouse, you are in for a universe of pain.
I strongly agree with this assessment :)
I have posted a bit more on this nearby, but Apache Kafka is well positioned as a compromise to support both of those truths: an orthogonal data warehouse full of sanitized purity and chatty apps writing crappy data to their hearts content.
By introducing a third system in between the data warehouse and transactional demands, Kafka decouples the communicating systems and introduces a clear separation of concerns for cross-system data communication (be they OLAP, or OLTP).
If your transactional data is crappy (mine is!), and you want your data warehouse pure (I do!), then Kafka can be a 'truthy' middle ground where compromises are made explicit and data digestion/transformation is explicitly mapped, and all clients can feast on data to their hearts content.
Your data warehouse can suck facts from Kafka (with ETL on either side of the operation, or even integrated into Kafka if you so desire), and you can keep Kafka channels loaded with micro-"Truth"s (current accounts, current employees, etc). That way apps get basically real-time simplified access to the data warehouse while your data warehouse gets a client streaming story that's wicked scalable. And no coupling in between...
It's a different approach than some mainstream solutions, but IMO hits a nice goldilocks zone between application and service communication and making data warehousing in parallel realistic and digestible. YMMV, naturally :)