Collider: An experimental Minecraft server

Collider is an experimental Minecraft server that operates with a parallel tick, meaning it can perform multiple tasks simultaneously. Unlike other servers that attempt to parallelize the tick, Collider achieves this without the need for locks, regions, thread ownership, or rules governing which mechanics can cross boundaries. Every aspect of the server is as simple as possible, and it manages to match vanilla 1.8.9 performance on a single core, while being four and a half times faster when running on six cores.

The server is written in Clojure and consists of approximately 5,500 lines of code. Its feature set is deliberately small, with the primary goal being to measure performance and provide a reference for working with the data model. Collider supports various Minecraft mechanics including light, water, lava, fire, block physics, dropped items, TNT, damage, a day and night cycle, world saving, chat with commands, and an inventory. The server runs on Minecraft 1.8.9 in a flat, creative, peaceful mode.

Unlike the region approach, which requires spatial independence by splitting the world into separate threads, Collider does not care about the players' locations. The only mob in the server is the sheep, with an AI that closely replicates its vanilla counterpart. Other world features, such as world loading for benchmarking purposes, prove the data model can handle real mechanics.

To set up the server, Java 21 or higher is required. Server properties are stored in a config.edn file located in the working directory. To replicate vanilla behavior, the decompiled 1.8.9 sources from MCP-919 were consulted.