Comment by maweki
It is nice to see a core group of Datalog enthusiasts persist, even though the current Datalog revival seems to be on the decline. The recent Datalog 2.0 conference was quite small compared to previous years and the second HYTRADBOI conference was very light on Datalog as well, while the first one had a quarter of submissions with Datalog connection.
I'm encouraged by the other commenters sharing their recent Datalog projects. I am currently building a set of data quality pipelines for a legacy SQL database in preparation of a huge software migration.
We find Datalog much more useful in identifying and looking for data quality issues thatn SQL, as the queries can be incredibly readable when well-structured.
No offense, but I wouldn't take Datalog 2.0's small attendance as an exemplar of Datalog's decline, even if I agree with that high-level point. Datalog 2.0 is a satellite workshop of LPNMR, a relatively-unknown European conference that was randomly held in Dallas. I myself attended Datalog 2.0 and also felt the event felt relatively sparse. I also had a paper (not my primary work, the first author is the real wizard of course :-) at the workshop. I myself saw relatively few folks in that space even attending that event--with the notable exception of some European folks (e.g., introducing the Nemo solver).
All of this is to say, I think Datalog 2.0's sparse attendance this year may be more indicative of the fact that it is a satellite workshop of an already-lesser-prestigious conference (itself not even the main event! That was ICLP!) rather than a lack of Datalog implementation excitement.
For what it's worth, none of what I'm saying is meant to rebut your high-level point that there is little novelty left in implementing raw Datalog engines. Of course I agree, the research space has moved far beyond that (arguably it did a while ago) and into more exotic problems involving things like streaming (HydroFlow), choice (Dusa), things that get closer to the general chase (e.g., Egglog's chase engine), etc. I don't think anyone disagrees that vanilla Datalog is boring, it's just that monotonic, chain-forward saturation (Horn clauses!) are a rich baseline with a well-understood engineering landscape (esp in the high-performance space) to build out more interesting theories (semirings, Z-sets, etc..).