Concurrent Chunk Management Engine - Forge

C2ME-Forge 0.2.0-forge.9.9.5 (Minecraft 1.20.1) - build 2026-10-30

Hotfix for forge.9.9.4. Everything else is the same as forge.9.9.4.

Fixed
• Memory leak during long pregenerations: on worlds where some chunks fall back to vanilla's density functions (seen with some world-generation setups), the density compiler kept every such chunk's noise data in memory for good. Over tens of thousands of chunks this filled the heap until the server ran out of memory (an r7000 Chunky pregen filled 12 GB after about 71,000 chunks). The compiler's two caches now let go of a chunk once it is finished. In our test of that path, memory kept per 1,000 generated chunks went from 157 MB to 6.8 MB (vanilla Minecraft: 9.7 MB). Every release since forge.9.9.1 had this leak.

Thanks to Rei for the report, the heap dump analysis and the fix.

Drop-in update. If long pregenerations ran your server out of memory, this is the fix. Support: https://discord.gg/s7BYs6Njj5