Your deduction goes a bit too far - yes, the technology demo in this post is in the same space as that case study, but no - the implementation is completely different.
Many firms replace their in-database processing with in-memory-like stores but it would be very difficult to achieve similarly low latency and still provide real-time updates with the solutions that you mentioned like Redis, ElasticSearch, etc. due to a number of the internal design features of these data stores.
The most fundamental issues are: a) inefficient memory allocation model hurting CPU cache usage, b) implementation model based on painful data serialization/deserialization transformations wasting both CPU and memory resources.
This is why we build and share this demo which enables you to achieve a 20x lower latency than other available options.
You may find a a bit more what's behind the demo in the Technology section here: https://ultrafastsearchengine.com/#/details