A lightweight performance fix for Eternal Starlight.
Eternal Starlight's book unlock system calls getOrCreateBookProgressions() for every inventory slot every 200 ticks. Each call hits data storage multiple times with no caching, causing significant TPS lag on servers - especially with multiple players online.
ESFix adds a simple mixin that caches book progression data for 5 seconds per player, dramatically reducing data storage access and improving server performance.
- NeoForge 1.21.1 - Eternal Starlight
Drop the jar in your mods folder alongside Eternal Starlight.