you can use "mem" comand try it.
Thanks, but 'mem' doesn't help this case. In game objects need to be deleted, rather than memory reclaimed.
Here are cases where it can get into this state:
1) There are tens of thousands of dropped block entities from someone setting off dozens of tnt
2) someone has collapsed a huge building, or a very large section of earth.
3) the game has over-spawned hordes, and they have piled up.
4) lot of players online in very different parts of the map have all done something big at about the same time.
5) more.
Every update loop takes seconds because there are so many entities to iterate through, and another update stacks onto the previous. Some symptoms are:
1) No new entity spawns.
a) You'll see no new wildlife or zombie spawns.
b) When people break blocks, no resource drops.
2) zombie zombies. Zombies stand frozen.
3) Structural integrity doesn't play out. Blocks turn into ghost entities but hang in space and prevent any action there.
4) the game otherwise seems to work... you can craft and loot and break blocks. Just, no entities will drop from them into the world.
A way to sweep/clear out all entities would be an effective intervention.
Thanks