[MC-100249] Falling Sand entitys don't fall in spawn chunks without player in overworld

In the spawn chunks, all entitys should always be moving. But if no player is in the overworld (all in nether/end), Falling sand entitys in the spawn chunks stop moving after a few seconds. This is a HUGE problem to mapmakers because falling redstone blocks are often used as clock to power command blocks which need to be in the spawn chunks to be always active.
Due to this bug, a lot of command creations that use falling sand as slow clock stop working if all players are in other dimensions that the overworld.

Linked issues

duplicates 1

MC-99673 Overworld spawn chunks not loaded in the Nether Resolved

Comments 1

Skylinerw 2016-03-29T19:36:48Z

Duplicate of MC-99673.

Copy/paste of comment on that report:

the spawn chunks are not unloaded. Entities and tile entities are simply no longer sent update ticks after 15 seconds of no players being in the overworld. Not all tile entities rely on update ticks though, such as command blocks. Command mechanisms that do not rely on certain tile entities nor regular entities will continue to function.
If you want to ensure the spawn chunks are always fully functional, you can send an entity to or from the overworld via a nether or end portal, which resets the 15-second timer. For example, you could have a clock in the spawn chunks that runs only when no players are in the overworld, which drops an item entity into an end portal every 14 seconds. This will keep the spawn chunks fully functional.

The reasoning behind this is very likely for performance.