Redis
This item was not updated in last three versions of the Radar. Should it have appeared in one of the more recent editions, there is a good chance it remains pertinent. However, if the item dates back further, its relevance may have diminished and our current evaluation could vary. Regrettably, our capacity to consistently revisit items from past Radar editions is limited.
Adopt
We prefer to use Redis as in-memory key-value data store for specific cases such as a custom cache or queue management solution. In such relatively simple cases a relational database would be overkill and not a good fit.
Redis is market leader in this area and fulfils all our needs.