Chiming in with my two cents…
When people have the luxury of working in environments where clusters are > massively over provisioned, LCS as a default makes a lot of sense, because > there's not much downside. The use cases where you'd actually fall behind > in compaction are pretty slim, so the negative impact isn't felt. > > Most people aren't doing this. Putting LCS as the default significantly > changes the performance profile of new clusters in a way that actively > harms a portion of the community. > Haddad's statement here resonates above everything else that's been said so far. It is this particular audience that I'm thinking first about not screwing over, everyone else is a step in front of them wrt knowing what compaction is and making an informed decision into changing it. My vote would be to focus on the move to make UCS the default. It's getting a lot of production time downstream. I don't believe there's much missing in the way of operator-facing useful introductory documentation (but what is missing is a blocker). In the interim I would support the idea of a log warning at startup for each table that is using the default STCS (that the operator hasn't explicitly set).
