Matthias Lukaszek

I can confirm this bug on my server with version 1.15.2

---- Minecraft Profiler Results ----
// Am I not running fast enough? :(Version: 1.15.2
Time span: 9435 ms
Tick span: 43 ticks
// This is approximately 4.56 ticks per second. It should be 20 ticks per second--- BEGIN PROFILE DUMP ---[00] tick(42/1) - 96.71%/96.71%
[01] |   levels(43/1) - 99.56%/98.38%
[02] |   |   world minecraft:overworld(43/1) - 90.34%/88.88%
[03] |   |   |   tick(43/1) - 99.88%/88.77%
[04] |   |   |   |   entities(43/1) - 94.11%/83.55%
[05] |   |   |   |   |   regular(43/1) - 99.40%/83.04%
[06] |   |   |   |   |   |   tick(49969/1162) - 97.55%/81.00%
[07] |   |   |   |   |   |   |   #getChunkCacheMiss 15416/358
[07] |   |   |   |   |   |   |   #getChunk 22761/529
[07] |   |   |   |   |   |   |   minecraft:pillager(645/15) - 55.68%/45.10%
[08] |   |   |   |   |   |   |   |   #tickNonPassenger 645/15
[08] |   |   |   |   |   |   |   |   ai(645/15) - 98.09%/44.24%
[09] |   |   |   |   |   |   |   |   |   newAi(645/15) - 99.98%/44.23%
[10] |   |   |   |   |   |   |   |   |   |   goalSelector(645/15) - 99.23%/43.89%
[11] |   |   |   |   |   |   |   |   |   |   |   goalTick(645/15) - 99.31%/43.59%
[12] |   |   |   |   |   |   |   |   |   |   |   |   #getChunkCacheMiss 5/0
[12] |   |   |   |   |   |   |   |   |   |   |   |   #getChunk 430/10
[12] |   |   |   |   |   |   |   |   |   |   |   |   pathfind(215/5) - 99.80%/43.50%
[13] |   |   |   |   |   |   |   |   |   |   |   |   |   #getChunkNow 7267/169
[12] |   |   |   |   |   |   |   |   |   |   |   |   unspecified(645/15) - 0.14%/0.06%
[12] |   |   |   |   |   |   |   |   |   |   |   |   canSee(190/4) - 0.06%/0.03%
[13] |   |   |   |   |   |   |   |   |   |   |   |   |   #getChunkCacheMiss 36/0
[13] |   |   |   |   |   |   |   |   |   |   |   |   |   #getChunk 1140/26
[11] |   |   |   |   |   |   |   |   |   |   |   goalUpdate(645/15) - 0.38%/0.17%
[12] |   |   |   |   |   |   |   |   |   |   |   |   #getChunkCacheMiss 4/0
[12] |   |   |   |   |   |   |   |   |   |   |   |   #getChunk 36/0
[12] |   |   |   |   |   |   |   |   |   |   |   |   #getChunkNow 9/0
[12] |   |   |   |   |   |   |   |   |   |   |   |   #getLoadedEntities 1/0
[12] |   |   |   |   |   |   |   |   |   |   |   |   unspecified(645/15) - 80.03%/0.13%
[12] |   |   |   |   |   |   |   |   |   |   |   |   canSee(201/5) - 19.97%/0.03%
[13] |   |   |   |   |   |   |   |   |   |   |   |   |   #getChunkCacheMiss 37/0
[13] |   |   |   |   |   |   |   |   |   |   |   |   |   #getChunk 2874/66
[11] |   |   |   |   |   |   |   |   |   |   |   unspecified(645/15) - 0.23%/0.10%
[11] |   |   |   |   |   |   |   |   |   |   |   goalCleanup(645/15) - 0.08%/0.03%

Linux 4.15.0-91-generic #92-Ubuntu SMP Fri Feb 28 11:09:48 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

openjdk version "1.8.0_242"
OpenJDK Runtime Environment (build 1.8.0_242-8u242-b08-0ubuntu3~18.04-b08)
OpenJDK 64-Bit Server VM (build 25.242-b08, mixed mode)

model name      : Intel(R) Core(TM) i3-2310M CPU @ 2.10GHz

The same happens with the client without a server and 8 GB of RAM.
I can run the server with different parameters for RAM etc. and it will still have the same issue.
Also the server only uses around 33% of the available RAM.

Here's ps aux for the current server in another biome. When I visit the jungle biome it suddenly goes up to 100% on one of the threads and stays there until it crashes due to a tick taking 60 seconds.

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
lucom    13398 18.4 33.3 2060732 684040 pts/1  Sl+  Sep06 117:12 java -Xmx1536M -Xincgc -jar minecraft_server.1.10.2.jar nogui

Also in 1.9.4