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MC-182904

Chunks stop generating and commands no longer work after several hours

I used a redstone machine to generate chunks by teleporting the player around the map at near the build limit. After this machine has been running for a couple of hours, chunks stop generating and the game no longer responds to any commands.

The machine is attached as g16.zip.

To reproduce: use a structure block to load the machine "g16" within the spawn chunks or forceloaded chunks. (The machine is 16×16 so it fits within one chunk.)
Start the machine by pressing the button.
The machine will teleport the player

Additional notes: the machine should stress test the terrain generation. Anyone with a fast PC should adjust the speed of the machine by reducing the number of redstone dust in the first pair of hoppers below 30. I used 25 on a dual-core machine, a quad-core machine should be able to manage with 15 or so. Render distance should be 10, maximum frames per second should be reduced as well: I capped my fps to 30.

Attachments

Comments 6

Affects 1.16 pre-3.

Reproduced in the Nether with the attached g16 redstone machine placed in a forceloaded chunk above the Nether ceiling at 0,0.

Reproducing this is most convenient to do if it's done overnight. Either the terrain will finish generating or the game will freeze at some point.

It appears to happen a bit less than 0.1% of the time (0.1% of all teleports). In a full run of the g16 machine (1894 teleports total) it happens about once on average.

Not so far as I know.
MC-159109 describes a redstone mechanism that apparently crosses chunk borders. The attached redstone mechanism is small enough to fit within a single chunk. If this machine is loaded aligned with a chunk, it will not cross any chunk borders. So far as I know, I have always loaded it aligned with a chunk; I often load it from a structure block placed at 0,0, and for the Nether tests it was always loaded in this way. The caveat here is that it's possible I may have loaded it across multiple chunks but I cannot recall ever having done this for a test.

Did you by any chance observe this in a more recent version of Minecraft?

bdm68

(Unassigned)

Unconfirmed

(Unassigned)

command_block

20w19a, 1.16 Release Candidate 1, 1.16

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