When a hopper or hopper minecart detects multiple inventories it can pull from or push into, it chooses one randomly without considering its fullness. This results in a reduced item transfer rate when some of the inventories it tries to pull from are empty, or when some of the inventories it tries to push into are full.
How to reproduce
Place the hoppers and minecarts as shown in the screenshot.
Put multiple minecarts with a chest on one of the hopper, put only one on the other.
Put a stack of items in one minecart chest on both sides.
→ ❌ The hopper with multiple (empty) minecart with chests above it will take longer to take it all out.
Linked issues
is duplicated by 3
Attachments
Comments 7
This also affects the input of items into these minecarts. Recreated this by stacking many minecarts full of the same item, and stacking one minecart that is empty. With a hopper pointing into the stack with items different from the common item in the full chests, the hopper will feed items through very slowly. This makes things very difficult for nexus storage systems.
Confirmed for Minecraft Snapshot 1.15.2 Pre-1. Please listen to why it is important that this issue be fixed.
This issue needs to be fixed before the full release of 1.15.2 as the issue creates unreliability in the game. The past few updates have been working towards removing these quirks such as The Flattening in 1.13 and prior, and the new rail placement feature in 1.15. Moving toward a more consistent game would involve the patching of this glitch.
Another reason for fixing this issue would be the current lack of storage system options. There are really only 2 viable storage systems at the current state of the game (Shulker systems, and standard Impulse sorting chest systems). Fixing this bug would add a third competitor to the list; The stack-able chest minecart storage system. I would love to build one of these in my world, however, the lack of speed when loading and unloading the minecarts makes the design almost unusable.
Thank you for listening, and constantly improving the game.
Definitely have to agree with Frank Zink here. I've also noticed that in jeb's experimental combat snapshots that knockback may potentially become deterministic, which is a similar idea to making hoppers interaction with entity inventories deterministic as well. From an in-game perspective, it doesn't make sense that the hoppers would fail to do their job when it is still possible.
From a implementation perspective, it likely wouldn't be a difficult change (moving from a random index to an iteration through available inventories that already have to be retrieved for indexing). Sure, it would cause the slightest amount more lag with potentially having to check more than one inventory per hopper per hopper-tick, but it would be virtually unnoticeable except in instances of many, many hoppers trying to interact with many, many entities with inventories.
And as Frank said, thank you again for listening to our feedback on this matter, esp. since it doesn't really affect the majority of the player-base (although one may argue that it could benefit the majority if fixed).
This seems to be caused by MC-124099.
Is this still an issue in the current Minecraft Snapshot 15w47c or later? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.