Seems like an interesting effort. A developer is building an alternative Java-based backend to Lemmy’s Rust-based one, with the goal of building in a handful of different features. The dev is looking at using this compatibility to migrate their instance over to the new platform, while allowing the community to use their apps of choice.
Sure, if the sort key is something readily available. But for scaled sort they have to compute relative size/activity of the communities the specific user is in. The cost isn’t the sort, it’s computing the metric.
I’m not talking about the literal sorting algorithm. Pretty sure scaled sort is exactly one more operation than hot.