CleanJoin is a server-side performance mod designed for high-population NeoForge servers and Arclight hybrid environments.
When many players join at the same time, the server main thread gets hammered with chunk loading, entity tracking and packet serialization all at once, causing TPS drops and watchdog crashes. CleanJoin addresses this with three systems working in parallel.
When a player joins, nearby chunks are loaded asynchronously in the background so the main thread never has to wait for disk I/O. Instead of sending hundreds of entity packets in the first tick, the initial entity sync is spread across the first two seconds after join, with hostile mobs and players always arriving first. Distant passive mobs that no player is near have their AI temporarily suspended on a worker thread, reducing pathfinding and goal calculation overhead during peak load.
The mod is fully compatible with Arclight servers running both NeoForge mods and Bukkit plugins simultaneously. All writes back to the game state are safely routed to the main thread to avoid conflicts with the Bukkit event system.
