Does a Data Lake Replace a Data Warehouse?
I’m biased here, and a firm believer that modern data warehousing is still very important. Therefore, I believe that a data lake, in an of itself, doesn’t entirely replace the need for a data warehouse (or data marts) which contain cleansed data in a user-friendly format. The data warehouse doesn’t absolutely have to be in a relational database anymore, but it does need a semantic layer which is easy to work with that most business users can access for the most common reporting needs.
On this question, my answer is “Absolutely not.” Data warehouses are designed to answer specific, known business questions. They’re great for regulatory reporting, quarterly reports to shareholders, weekly reports to management, etc. Data lakes are designed for ad hoc analysis of information. Read the whole thing.