The bug
While teleporting between dimensions using /execute in <dimension> run teleport @s (or similar) the client got stuck at the "Loading terrain..." screen when I teleported from the overworld to the nether (previous teleports were successful). However it remained responsive.
It appears the underlying problem is that the server got stuck while performing the command (see attached jstack outputs):
19w03c
at java.lang.Thread.yield(Native Method)
at uq.b(SourceFile:147)
at uq.a(SourceFile:131)
at bci.a(SourceFile:260)
at bcm.a(SourceFile:120)
at bci.c(SourceFile:255)
at bci.a(SourceFile:590)
at ur.a(SourceFile:570)
at ut.a(SourceFile:1269)
at td.a(SourceFile:164)
at td.a(SourceFile:138)
at td.h(SourceFile:51)
at td$$Lambda$1917/813607430.run(Unknown Source)
at com.mojang.brigadier.CommandDispatcher.execute(CommandDispatcher.java:132)
at com.mojang.brigadier.CommandDispatcher.execute(CommandDispatcher.java:72)
at cb.a(SourceFile:223)
at vl.c(SourceFile:1088)
at vl.a(SourceFile:1075)
at ng.a(SourceFile:37)
at ng.a(SourceFile:9)
at jr.a(SourceFile:15)
at jr$$Lambda$2295/174447671.run(Unknown Source)
at qs.run(SourceFile:18)
at net.minecraft.server.MinecraftServer.p(SourceFile:694)
at net.minecraft.server.MinecraftServer.o(SourceFile:665)
at net.minecraft.server.MinecraftServer.run(SourceFile:624)
at java.lang.Thread.run(Thread.java:745)The following might have been logged after using the command, though I am not completely sure and it might be the log messages of a previous teleport:
01:04:52 net.minecraft.server.MinecraftServer [Marcono1234: Teleported Marcono1234 to Marcono1234]
01:04:52 drn Saving and pausing game...
01:04:52 crd [CHAT] Teleported Marcono1234 to Marcono1234
01:04:52 net.minecraft.server.MinecraftServer Saving chunks for level '1.14 test'/minecraft:the_nether
01:04:52 bsu ThreadedAnvilChunkStorage (DIM-1): All chunks are saved
01:04:52 net.minecraft.server.MinecraftServer Saving chunks for level '1.14 test'/minecraft:overworld
01:04:52 bsu ThreadedAnvilChunkStorage (1_14 test): All chunks are saved
01:04:52 net.minecraft.server.MinecraftServer Saving chunks for level '1.14 test'/minecraft:the_end
01:04:52 bsu ThreadedAnvilChunkStorage (DIM1): All chunks are savedForcing a crash failed, the client became unresponsive after logging "[CHAT] [Debug]: Crashing in 1...". The thread dump for this is
[media].
Attachments
Comments 11
Still an issue in 19w46b.
@@unknown, is the server really getting stuck for you, i.e. not doing anything regardless of how long you wait, or does is just take long to load the nether?
Sometimes the Nether loads after waiting for about three minutes, sometimes it doesn't. Though when it doesn't load after five to ten minutes I will sometimes close the process in Task Manager (Windows 10).
This also happens if I throw items into nether portals to force load the Nether chunks.
It doesn't happen all the time.
I have noticed that it's a bit more likely to happen after Nether chunks have recently unloaded. If I travel from the Nether to the Overworld and wait a minute or two before returning to the Nether, the Nether won't load.
When the Nether isn't loading, the server appears to hang. Mobs don't move, mobs don't make sounds, broken blocks don't drop. etc.
NOTE: This is the observed behaviour with 1.14.4. It is better in 1.15 pre-3, but some more testing is needed to examine this.
It happened to me twice in a new world. I have included a brief description of what I was doing along with the game log from the launcher. Version is 1.14.4. I used this version to get some steps to reproduce that were fairly reliable, but your results may be different.
===
(Render distance is set to 15 chunks.)
Create a new default world with seed 1 in creative mode.
Set difficulty to Peaceful.
Turn off daylight cycle.
Set time to 6000 (eternal noon).
Wait for terrain to finish loading.
/fill -160 63 272 -176 63 288 minecraft:polished_andesite
Collect the drops to keep them out of the portal.
Build a portal at -168 280.
Enclose the portal with fences to stop animals wandering into it.
Light the portal.
Enter the portal.
Wait for terrain to load new terrain -> Log: "Can't keep up! Is the server overloaded? Running 126073ms or 2521 ticks behind"
Fence off Nether portal and make it safe by building a platform (it will spawn on a 1-thick block of Netherrack over lava).
Go to -97 90 38 by flying in creative mode
/fill -93 89 36 -101 89 41 minecraft:polished_andesite
Build a Nether portal at -97 37 to -97 40.
Fence off the Nether portal.
Light the portal.
Enter the portal.
Wait for terrain to load -> Terminated with Task Manager after about 19 minutes because it wasn't making progress
===
In 1.14.4, the delay was very noticeable. In 1.15 pre-3, the performance is much better. I noticed no significant lag entering Nether portals in either direction.
Five to ten minutes sounds pretty horrible, but I am not sure if this is actually the bug described here. In that case the server would (unless the code changed) very likely hang forever.
Does your computer meet the minimal system requirements?
Can this still be reproduced in the latest 1.16 development snapshot?
@Michael Wobst i have this exact issue on the recent 1.16 snapshots and pre-releases also, i dont know if its related to this but sometimes whenever i enter e nether portal it just gets stuck and it never loads, i hope mojang can fix this
Been happening since 20w21a including pre-2 to @unknown according to discord, so added pre-2 to affected versions
sorry if im getting annoying but i just want to play but it sucks when i freeze after entering the nether
Can this still be reproduced in 1.18-pre3?
I have been getting slow loading of worlds after passing through Nether portals, particularly when entering the Nether in an area where there are several Nether portals in the vicinity (within 128 blocks). It is not unusual for me to experience load times of three minutes or more when entering the Nether.
23:42:07 net.minecraft.server.MinecraftServer Server thread warn Can't keep up! Is the server overloaded? Running 186029ms or 3720 ticks behind