Investigating Bug: Leak: ChunkLoader

[Darkweasam]

Enter a brief description of what is broken Leak: ChunkLoader

What version of Minecraft are you using? 1.14.4

What server jar are you using? PaperSpigot v226

What is this a bug report for? MythicMobs

What version of the plugin are you using? v4.7.2

Describe the bug. Be as specific as possible, images or short gifs/videos are welcome but save configuration files for later sections. Write a whole paragraph if needed, help us bug testers replicate your issue!
MythicMobs::Task: io.lumine.xikage.mythicmobs.adapters.bukkit.listeners.ChunkListeners.ChunkLoader (Single)

AND

MythicMobs::Event: i.l.x.m.a.b.l.ChunkListeners (ChunkUnloadEvent)

causes several lag, sometimes when a player enter /spawn the server catches a great lag spike, sometimes even a timeout for everyone

Would like to know what causes the plugin for these tasks, I did not have this issue in previous versions

Example Configurations
Default config

Image of leak:

Every bump is caused by these two, it usually happens whenever someone goes to the spawn point of ANY world


Rarely appearing error: https://pastebin.com/HhGSJsTq

 

[iTzCascadexX]

I suspect you're using HolographicDisplays, a plugin (which on 1.14 versions of Minecraft) contains a serious bug with chunks that causes them to rapidly load and unload chunks. This, in turn, makes MythicMobs scan for mobs in chunks that don't have any, also at a rapid pace. I would suggest updating any of your applicable plugins/server where possible.

 

[Darkweasam]

EDIT: updated with error that spams and stuns the server

@iTzCascadexX I dont think its holographicdisplays, the error mentions "scores"

 

[iTzCascadexX]

23.01 11:16:26 [Server] Startup [16:16:26 ERROR]: io.lumine.xikage.mythicmobs.mobs.MobManager.determineMobType(MobManager.java:755)
23.01 11:16:26 [Server] Startup [16:16:26 ERROR]: io.lumine.xikage.mythicmobs.mobs.MobManager.registerActiveMob(MobManager.java:414)
23.01 11:16:26 [Server] Startup [16:16:26 ERROR]: io.lumine.xikage.mythicmobs.mobs.MobManager.getMythicMobInstance(MobManager.java:462)
23.01 11:16:26 [Server] Startup [16:16:26 ERROR]: io.lumine.xikage.mythicmobs.mobs.MobManager.getMythicMobInstance(MobManager.java:451)
23.01 11:16:26 [Server] Startup [16:16:26 ERROR]: io.lumine.xikage.mythicmobs.adapters.bukkit.listeners.ChunkListeners.ChunkUnloadedEvent(ChunkListeners.java:101)
23.01 11:16:26 [Server] Startup [16:16:26 ERROR]:

These errors are classic examples of the HolographicDisplays bug. The "Server Thread" is basically the main thread that the server runs on, a lot of things pass through there, majority of things there won't be causing your issues.

The HolographicDisplays error was a silent one that caused mayhem with chunks and their data. You mentioned this only happens at spawn, I can imagine all your holograms are there too.

 

[Darkweasam]

I did not touch HolographicDisplays since a long time, I didnt think it would be an issue now. But just to make sure, I made a test where I took it out.

The issue is still here without HD plugin
Also I said it happens in ANY world, lag spike happens especially if the spawn point of those worlds was unloaded before

 

[Darkweasam]

I was able to reproduce the issue using three plugins:

Mythicmobs 4.7.2 (default config)
Multiverse
Essentials

It works if you are a single player on the server, but the lag is way smaller
All you need to do is to switch between world quickly and do a /timings paste afterwards

 

[iTzCascadexX]

Huh, interesting. I can only replicate this with pre-1.15 versions of HolographicDisplays. I wouldn't know what causes this otherwise.

 

[Darkweasam]

I also have these two spams:
https://pastebin.com/cGB7FetC
https://pastebin.com/UPkkPbCL
Even if the whole MythicMobs folder is deleted and regenerated

UPDATE:
Used plugin spark to determine the roots: