Glad to hear that you like Data Engineering and also that my posts are useful to you :)
I agree with you that it's sometimes difficult to figure out what data structures are used under the hood of different software products. If it is open source you can at least dig into the code. But the official websites mostly contain buzzwords and marketing figures.
If you want to know more about a specific product it's also useful to see if there are mailing lists, chats, or forums you can join. When working on this article I also talked to the developer of SwayDB, clarifying a few questions I had about the internals.
And one more thing. In case you don't know it already, there is an amazing collection of articles about the correctness and robustness of different databases and distributed systems: aphyr.com/tags/Jepsen I like to read this to get a different view on the technologies.
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