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  1. Minecraft: Java Edition
  2. MC-191538

The game becomes extremely laggy and the server stalls/crashes after a while when certain structures try to generate above y 255 in custom worlds

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    Details

    • Type: Bug
    • Status: Open
    • Resolution: Unresolved
    • Affects Version/s: 1.16, 1.16.1, 21w03a, 1.16.5
    • Fix Version/s: None
    • Labels:
      None
    • Confirmation Status:
      Confirmed
    • Category:
      Custom Worlds
    • Mojang Priority:
      Low

      Description

      The Bug

      I noticed this when trying to generate a custom dimension that generates a ceiling at y=255 with overworld biomes.
      The log was being spammed with errors like these:

      [03:51:23] [Server thread/WARN]: Tried to load a DUMMY block entity @ fu{x=-137, y=260, z=13} but found not block entity block Block{minecraft:air} at location
      [03:51:23] [Server thread/WARN]: Tried to load a block entity for block Block{minecraft:air} but failed at location fu{x=-137, y=260, z=13}
      

      Note how y is above the world limit.
      In this particular case, when going to that location, it appears like a village tried to generate at this location.
      Changing separation and spacing to 4095 and 4096 for villages seemed to solve the issue. I am not sure if other structures might be affected as well.

      How to Reproduce

      1. Generate a world spawn with the following preset: overworld_ceiling_255-1.json
      2. /execute in buggy:game_breaking_experience run tp @s 752 256 -208
        The game gets extremely laggy

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              Assignee:
              Unassigned Unassigned
              Reporter:
              Schortan [Mod] NeunEinser
              Votes:
              3 Vote for this issue
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              4 Start watching this issue

                Dates

                Created:
                Updated:
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