Direct answer
Spigot unload-frozen-chunks is an experimental option affecting whether chunks may unload when ticks are frozen with /tick freeze. It is not a general-purpose chunk unload optimization.
How to check it
- Check the generated
spigot.yml, confirm what server-side/tick freezedoes on your build and take a test-world backup before experimenting. - Record the original configuration or test conditions, capture a profile or a repeatable observation, and identify the affected world or player group.
- Make the measurement under the same player count and workload you will later use to verify the change.
What to change
Use this only when reproducing frozen-tick behavior for debugging. The setting may change what loaded chunks you can inspect after freeze and is not relevant to ordinary TPS improvement.
Do not enable it to address normal memory growth without a reproducible frozen-tick test.
Software and version notes
Check the active version and generated configuration before copying paths or values. Different forks and mod loaders may implement this behavior differently.
This article is written for Paper / compatible servers. Configuration keys and defaults can move between versions. The source material checked for this page includes PaperMC spigot.yml reference. If your server is Folia, Leaf, Purpur, Fabric, Forge, NeoForge, or another fork/loader, do not assume a Paper-only setting exists or behaves identically.
Verify the result
Repeat the same test with the same software build, player count and world activity. Compare the targeted symptom and any spark measurements, then check that intended game mechanics still work. If the change does not produce a reproducible improvement, revert to the recorded baseline.