[MC-28346] Mob cap doesnt properly adjust based off of players in the area.

The number of mobs is not properly controlled by each player. Thus, if a player builds a dark room and is on for a while, they will get all of the mobs. If a second player then joins and is near a dark room, the mob cap doubles. This, the first player gets 1.5 times the normal mobs, and the second player gets .5 times the normal. The fact that another player controls the amount of mobs and the difficulty for a distant, separate player is clearly a bug.

Real bug report format:
What I expected to happen was...:
When a player logs in, the average amount of mobs that spawn near them is the same as the first player that spawns.
What actually happens is...:
The second player gets half the mobs of the first, the third 1/3 the amound of the second, ect.

Steps to Reproduce:

1. Create a superflat world with some preset that has controlled amounts of mob spawning, eg "7,10x0,1,32x0,2x7"
2. Run that world in mp.
3. Join and teleport to "1000,46,1000".
4. Wait for about 5 minuites until the mobcap is reached (e in f3)
5. Have another player join, and teleport to "-1000,46,-1000".
6. Wait 5 minuites.
7. Note how the amount of mobs by player 1 is about 1.5 times the amount at player 2. How does this make sense?

Watch: http://www.youtube.com/watch?v=q_DwPJZd2BU

Linked issues

is duplicated by 3

MC-28341 Mob cap doesnt properly adjust based off of players in the area. Resolved

MC-45472 Minecraft doesn't use a "player-per-chunk" based mob cap Resolved

MC-69575 Multiplayer: Mob spawning severely decreases with multiple players Resolved

Comments 42

polychoron 2013-08-09T01:01:17Z

MODS: THIS IS NOT A DUPLICATE OF MC-2536.

All of the previous bug reports have been removed. This bug is not related to MC-2536, so please do not remove it!

A video that explains this is detail is:
https://www.youtube.com/watch?v=q_DwPJZd2BU

pokechu22 2013-08-09T01:03:50Z

What will it take for this not to be marked as duplicate?
Its a actual bug.
See also:
http://www.youtube.com/watch?v=q_DwPJZd2BU&lc=x5A39kZV71nNWwxVVU2kCunZQO0G408-kk9FQJeSE_IWANNA

Tino 2013-08-09T01:05:58Z

http://www.youtube.com/watch?v=q_DwPJZd2BU

Ben Isbell 2013-08-09T01:06:03Z

MODS the reason this is getting up-voted quickly is because http://de.twitch.tv/jl2579

pokechu22 2013-08-09T01:07:26Z

@Ben Isbell
And because it is a real bug and the only way it would ever be fixed is if we say it needs to be fixed _

32 more comments

Burgru 2013-08-09T01:14:03Z

This is a bug that is very important for ZipKrowd. They love their mob spawners 🙂

Neospector 2013-08-09T01:16:19Z

If I had to hazard a guess, I'd say works as intended. From the Wiki:

In multiplayer, chunks that are in range of multiple players are only counted once. So the more spread out the players are, the more chunks will be covered and the higher the caps will be.

So if the players are a certain distance apart and rendering certain chunks differently (such as with a lower render distance), it's theoretically possible that the mob count would be raised in this manner...

pokechu22 2013-08-09T01:22:47Z

If I had to hazard a guess, I'd say works as intended. From the Wiki:

In multiplayer, chunks that are in range of multiple players are only counted once. So the more spread out the players are, the more chunks will be covered and the higher the caps will be.

So if the players are a certain distance apart and rendering certain chunks differently (such as with a lower render distance), it's theoretically possible that the mob count would be raised in this manner...

Look, that's a statement from what the current state is. Its like saying "Ok, so this buggy property exists" and writing that on the wiki makes in not a bug.

Neospector 2013-08-09T01:32:22Z

Pokechu22: The Wiki isn't always accurate, no. But it tends to be fairly accurate to an extent. Especially since the last change to spawning in the game was in 1.0.0 and looking through the revision history I cannot find any immediate change to multiplayer mob spawning in the revision history.
I'm only a player like you and all I can do is guess given the amount of information I have available.

pokechu22 2013-08-09T01:34:43Z

@Neospector
That doesn't mean it isn't a bug.

I'm only a player like you and all I can do is guess given the amount of information I have available.

Well, actually, this was incited by a anylization of the source code,

http://www.youtube.com/watch?v=q_DwPJZd2BU&lc=x5A39kZV71nNWwxVVU2kCunZQO0G408-kk9FQJeSE_IWANNA
It is a bug; this doesn't make sense anyway.

Neospector 2013-08-09T01:35:37Z

It doesn't mean it is one either. So given that there's more evidence leaning towards "Works as Intended", that's my opinion.
Edit: Also, according to that video, it makes perfect sense. The mob cap is only raised a little bit in order to reduce lag caused by the mobs. If you were to eliminate all hostile mobs and let them respawn, they would be (assuming ideal conditions) divided equally between the players.

pokechu22 2013-08-09T01:57:27Z

If you were to eliminate all hostile mobs and let them respawn, they would be (assuming ideal conditions) divided equally between the players.

And that's a if, which isn't the case. Test it; its uneven.

Neospector 2013-08-09T02:05:03Z

Uneven because a lot of mobs spawned at the first player before another player joined and filled up the mob cap. Doesn't seem to be "buggy" to me. Just seems that you filled up the mob cap before another player joined.

pokechu22 2013-08-09T02:07:30Z

Uneven because a lot of mobs spawned at the first player before another player joined and filled up the mob cap. Doesn't seem to be "buggy" to me. Just seems that you filled up the mob cap before another player joined.

And then another player joins, and the first player has more total mobs then the second. The first already WAS at cap, then exceeds the cap; they get more then their share.

Neospector 2013-08-09T02:13:47Z

The mob cap gets raised. The mob cap is universal, not focused on the players. Mob spawns occur everywhere where it's valid. I see unexpected functionality, but nothing buggy, broken, or bad for the game necessarily.

pokechu22 2013-08-09T02:18:14Z

The mob cap gets raised. The mob cap is universal, not focused on the players. Mob spawns occur everywhere where it's valid. I see unexpected functionality, but nothing buggy, broken, or bad for the game necessarily.

THE PROBLEM IS THAT THE CAP IS UNIVERSAL
Really. It gives one player more mobs than the others; if someone afk's at spawn with a dark area, they will have all the mobs if another player keeps killing their mobs at a perfect mob grinder.

Neospector 2013-08-09T02:40:24Z

Except universal mob cap is intended, I know that much for sure. To change it, you need to go to the Forums or Reddit. Intended feature, not a bug, therefore does not belong on this website.

pokechu22 2013-08-09T02:45:36Z

The way it works generates buggy side effects. Are you saying that uneven mobs per player is intentional?
You need to change intended behaviours to fix bugs.

Thijs Lacquet 2013-08-09T19:36:47Z

The fact that there are less mobs, when there are more players on a server is buggy. Something like a mobcap, cant be universal, mobfarms shouldn't be affected by another player over 1000 blocks away, but that's how it is right know. So this is not a feature, but a bug.

Neospector 2013-08-10T14:21:56Z

Thijs, Pokechu22: Just because something doesn't work the way you want it to does not make it a bug. Universal mob cap is works as intended, so you need to discuss it's change on the forums.
Furthermore, Thijs, it has been made clear that mob grinders are relatively disliked by Mojang. So I doubt that argument would get it changed in the first place
l I still see no issue; when the mobs are killed, it will balance out, and eventually everything will spawn evenly.
Let me make it clear, I'm not trying to be mean or rude, I'm just saying mob cap being universal is intended, and to make this changed you need to take it up on the Forums or Reddit. Trying to keep it here will not make it any more likely to be changed. And, again, I'm just a normal user, and a mod or dev can write off my opinion in an instant.

pokechu22 2013-08-10T17:48:46Z

Thijs, Pokechu22: Just because something doesn't work the way you want it to does not make it a bug. Universal mob cap is works as intended, so you need to discuss it's change on the forums.
Furthermore, Thijs, it has been made clear that mob grinders are relatively disliked by Mojang. So I doubt that argument would get it changed in the first place
l I still see no issue; when the mobs are killed, it will balance out, and eventually everything will spawn evenly.
Let me make it clear, I'm not trying to be mean or rude, I'm just saying mob cap being universal is intended, and to make this changed you need to take it up on the Forums or Reddit. Trying to keep it here will not make it any more likely to be changed. And, again, I'm just a normal user, and a mod or dev can write off my opinion in an instant.

Well, people only post bug reports most of the time because the thing isn't working the way they want it or the way doesn't make sense. There are several other behavours that point out a problem and sugest a solution. So making less work for Mojang is bad?

Furthermore, Thijs, it has been made clear that mob grinders are relatively disliked by Mojang. So I doubt that argument would get it changed in the first place

Then why did they add hoppers? To collect the cobble you drop on the ground, not the drops from a 24-7 mob farm?

l I still see no issue; when the mobs are killed, it will balance out, and eventually everything will spawn evenly.

Well, if one player is afk, they hoard all the mobs, until there is none left. If other players keep reloging, you could reach a point where there are never any mobs. Basicly, this bug lets you make no mobs spawn due to a afk player.

Thijs Lacquet 2013-08-11T08:50:08Z

Neospectator, This could also give problems when players are AFK, because all the mobs will spawn in just the area of the AFK-ing player, and when other players log in, then they won't have mobs in their area.

The mob cap is similar to this both in SSP and in SMP when the people are close to each other, it completely works as how its suspected to be, but it starts giving problems when someone is AFK-ing, or when multiple people are in different area's on a server, mojang just didn't consider these kind of situations. And a lot of people will agree with me, that letting one player AFK should not remove the mobs for the other players. Mojang didn't intend that it is possible to use this trick.

Also, mojang added hoppers in 1.5, its ability to pickup items is mostly used by mob farms, if Mojang wanted to ban those farms, they could just remove the possibility for hoppers to pickup items.

Neospector 2013-08-11T16:37:25Z

Well, people only post bug reports most of the time because the thing isn't working the way they want it or the way doesn't make sense. There are several other behavours that point out a problem and sugest a solution. So making less work for Mojang is bad?

You're supposed to post bug reports for bugs, not things that annoy you. Hence, lots of issues with MC-3066

Then why did they add hoppers? To collect the cobble you drop on the ground, not the drops from a 24-7 mob farm?

Also, mojang added hoppers in 1.5, its ability to pickup items is mostly used by mob farms, if Mojang wanted to ban those farms, they could just remove the possibility for hoppers to pickup items.

Apologies if I sound rude, but you two have a very limited scope of the use of hoppers...I would suggest experimenting more with how they can be used in custom maps and redstone-powered shops. But this is off-topic.

As for AFK players, well, there you go. You've pointed out an issue to me. It's not as imperative as you mentioned, as you forget that mobs also burn in the daylight, so a player can't just "take" all the mob spawns for him/herself, but it is an issue that an AFK player can subtract from the total mob count. It is not an issue that online players can weaken mob grinders, however.

pokechu22 2013-08-11T18:52:47Z

Apologies if I sound rude, but you two have a very limited scope of the use of hoppers...I would suggest experimenting more with how they can be used in custom maps and redstone-powered shops. But this is off-topic.

Yea, hoppers do have other uses, this is just one of the more obvios and immediately useful ones.

As for AFK players, well, there you go. You've pointed out an issue to me. It's not as imperative as you mentioned, as you forget that mobs also burn in the daylight, so a player can't just "take" all the mob spawns for him/herself, but it is an issue that an AFK player can subtract from the total mob count. It is not an issue that online players can weaken mob grinders, however

True, but mobs spawning in caves and creepers don't burn. If you wait too long it can become inbalenced.

As for things that anoy you not being bugs, that's sometimes the case, and sometimes not. It was my best attempt at explaining.

pokechu22 2013-08-31T19:38:34Z

Here's the other effect of this:
Suppose you have a giant sheep farm at spawn.
Spawn is always loaded.
Thus, you will have 5000 sheep always loaded.
Supose you wander around then.
The game will look at the number of animals, and see that there are 5000 there, past the mob cap, despite the fact that there are no animals for miles, thus no animals ever spawn.

Thijs Lacquet 2013-09-01T12:01:37Z

Or another possible abuse:
Have 200 zombie's with 1 peace of cobble in their hand (so they wont despawn), in a small box at the border of the spawn chunks. Have a system which transport them all (with pistons or water) 1 or 2 blocks to the side. So they will leave the spawnchunks.
With this mechanism, you could completely turn on and off mob spawning with redstone in vanilla survival.

Talven81 2013-11-27T19:56:50Z

Is this still a concern in the current Minecraft version 1.7.2 / Launcher version 1.3.4 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.

alexander 2014-01-02T17:29:10Z

This has been an issue since the inception of smp.
In fact, this can, and indeed was on my server, exploited by a few players to obtain vast quantities of tnt.
They waited for the server to be clear of players, built a mob farming mechanism, and towered up to the sky limit in various locations around the map in order to artificially raise the mob cap.
This bug also has implications for new players joining a server, if player A is advanced and has explored most of the caves in his area, then player B joins and starts a base in newly generated terrain, then player B will experience abnormally high numbers of mobs, due to the higher number of spawn-able spaces in his area.
Furthermore, several major game events, namely finding the end and defeating the wither, depend upon being able to find sufficient quantities of certain mobs, so this issue opens up the possibility of exploits involving those mechanics too.
Another problem can arise when a player afk's at his/her xp farm, I have had players afk for an hour or more, building up monsters and practically shutting off mob spawning server wide.
There are also several more minor dependencies, slime for sticky pistons, string for bows etcetera.
If you ask me this is a major, but curiously ignored issue that affects a great many game mechanics.
Now, I am no java programmer, and I speak from ignorance when it comes to minecraft, but surely the implementation of mob caps on a per-player basis in smp can't be that difficult?

Thijs Lacquet 2014-01-04T10:50:55Z

Alexander, the zipcrowd guys made a server side mod which does exactly what the vanilla server should do. The video is linked in the discription.

alexander 2014-01-04T17:35:25Z

I was not aware of this!
I hope that this is implemented.

galaxy_2alex 2014-01-23T14:58:18Z

Is this still a concern in the current Minecraft version 1.7.4 / Launcher version 1.3.8 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.

Thijs Lacquet 2014-01-23T15:12:29Z

Galaxy, this bug still affects current Minecraft versions, like 1.7.4.

Deleted account 2014-03-27T15:38:00Z

Is this still a concern in the current Minecraft version 14w11b 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.

Pierre Waldén 2014-06-27T13:44:21Z

This is not a bug in my opinion, rather gameplay mechanics.

If this should be changed or not is another question, and it should be considered as a gameplay balance issue with all the pros and cons of changing it.

An example of gameplay that can be elevated with this is for example if you are playing as a team on a server and light up most of the area you usually are in, while having a mob spawner together that everyone can use. Obviously everyone gets more spawns where they want them to by working together making use of this mechanic.

(I am netiher for or against a change of this, I just dont think that it should be considered a bug)

Anthony Martin 2014-07-28T02:39:51Z

I believe as of 14w30c, this problem persists. I'm seeing the following log entries. In the past, this meant that there were corrupt chunks, but whenever I check these locations, the chunks are fine. The server spits out these messages much more often when view-distance=3 is set and more than one player is logged in:

[19:05:42] [Server thread/WARN]: Wrong location! (1417, -851) should be (1416, -851), abo['Cow'/1604, l='swim3', x=22672.20, y=67.00, z=-13615.12]
[19:05:42] [Server thread/WARN]: Wrong location! (1416, -852) should be (1416, -851), abo['Cow'/1612, l='swim3', x=22666.74, y=67.00, z=-13616.00]
[19:05:42] [Server thread/WARN]: Wrong location! (1417, -851) should be (1416, -851), abo['Cow'/1614, l='swim3', x=22673.74, y=67.00, z=-13613.80]
[19:09:25] [Server thread/WARN]: Wrong location! (1413, -854) should be (1413, -853), acf['Sheep'/82234, l='swim3', x=22615.93, y=65.00, z=-13649.01]
[19:09:25] [Server thread/WARN]: Wrong location! (1416, -852) should be (1417, -852), abo['Cow'/82293, l='swim3', x=22671.53, y=67.00, z=-13616.86]
[19:10:04] [Server thread/WARN]: Wrong location! (1413, -846) should be (1412, -847), acf['Sheep'/85119, l='swim3', x=22608.08, y=70.00, z=-13535.85]
[19:10:04] [Server thread/WARN]: Wrong location! (1411, -847) should be (1412, -847), aea['Creeper'/85120, l='swim3', x=22582.91, y=68.00, z=-13550.39]
[19:10:32] [Server thread/WARN]: Wrong location! (-1057, -6206) should be (-1056, -6206), abo['Cow'/90156, l='swim3', x=-16900.63, y=72.00, z=-99286.93]
[19:10:32] [Server thread/WARN]: Wrong location! (-1057, -6206) should be (-1056, -6206), abo['Cow'/90158, l='swim3', x=-16896.97, y=72.00, z=-99283.16]
[19:10:32] [Server thread/WARN]: Wrong location! (-1057, -6206) should be (-1056, -6206), abo['Cow'/90161, l='swim3', x=-16900.80, y=72.00, z=-99283.07]
[19:10:32] [Server thread/WARN]: Wrong location! (-1057, -6206) should be (-1056, -6205), abn['Chicken'/90163, l='swim3', x=-16904.96, y=71.00, z=-99281.07]
[19:10:32] [Server thread/WARN]: Wrong location! (-1057, -6205) should be (-1056, -6205), acf['Sheep'/90166, l='swim3', x=-16900.02, y=71.00, z=-99277.93]
[19:10:32] [Server thread/WARN]: Wrong location! (-1057, -6205) should be (-1056, -6205), acf['Sheep'/90167, l='swim3', x=-16903.69, y=71.00, z=-99277.62]
[19:10:32] [Server thread/WARN]: Wrong location! (-1057, -6205) should be (-1056, -6205), acf['Sheep'/90169, l='swim3', x=-16896.84, y=71.00, z=-99277.36]
[19:10:32] [Server thread/WARN]: Wrong location! (-1057, -6205) should be (-1056, -6205), acf['Sheep'/90170, l='swim3', x=-16897.84, y=71.00, z=-99274.50]
[19:10:32] [Server thread/WARN]: Wrong location! (-1057, -6205) should be (-1056, -6205), acf['Sheep'/90171, l='swim3', x=-16903.93, y=71.00, z=-99275.76]
[19:10:32] [Server thread/WARN]: Wrong location! (-1057, -6205) should be (-1056, -6205), acf['Sheep'/90172, l='swim3', x=-16900.93, y=71.00, z=-99273.07]
[19:10:32] [Server thread/WARN]: Wrong location! (-1057, -6205) should be (-1056, -6205), acf['Sheep'/90175, l='swim3', x=-16898.89, y=71.00, z=-99275.87]
[19:10:33] [Server thread/WARN]: Wrong location! (-1053, -6201) should be (-1055, -6201), abk['Bat'/90180, l='swim3', x=-16844.25, y=24.03, z=-99210.91]
[19:11:21] [Server thread/WARN]: Wrong location! (1416, -849) should be (1415, -848), afz['Villager'/149313, l='swim3', x=22656.24, y=68.00, z=-13568.38]
[19:11:29] [Server thread/WARN]: Wrong location! (1421, -853) should be (1422, -853), acf['Sheep'/164978, l='swim3', x=22751.45, y=65.00, z=-13636.22]
[19:11:31] [Server thread/WARN]: Wrong location! (-1063, -6209) should be (-1062, -6208), afg['Skeleton'/164993, l='swim3', x=-16995.30, y=20.00, z=-99330.32]
[19:11:53] [Server thread/WARN]: Wrong location! (-1059, -6207) should be (-1059, -6208), aci['Squid'/177818, l='swim3', x=-16929.75, y=58.62, z=-99311.82]
[19:11:54] [Server thread/WARN]: Wrong location! (1415, -849) should be (1416, -849), afz['Villager'/178416, l='swim3', x=22641.49, y=67.00, z=-13573.09]
[19:12:07] [Server thread/WARN]: Wrong location! (1417, -848) should be (1416, -848), afz['Villager'/182221, l='swim3', x=22672.50, y=68.00, z=-13556.26]
[19:12:07] [Server thread/WARN]: Wrong location! (1416, -847) should be (1416, -848), afz['Villager'/182222, l='swim3', x=22656.62, y=68.00, z=-13551.73]
[19:12:07] [Server thread/WARN]: Wrong location! (1416, -851) should be (1416, -850), abo['Cow'/182230, l='swim3', x=22670.36, y=67.00, z=-13602.24]
[19:12:20] [Server thread/WARN]: Wrong location! (1415, -848) should be (1415, -849), ack['Iron Golem'/198266, l='swim3', x=22648.80, y=67.50, z=-13566.60]
[19:12:24] [Server thread/WARN]: Wrong location! (-1061, -6202) should be (-1062, -6202), aci['Squid'/210743, l='swim3', x=-16975.38, y=57.80, z=-99218.22]
[19:12:24] [Server thread/WARN]: Wrong location! (-1062, -6204) should be (-1062, -6206), abk['Bat'/210794, l='swim3', x=-16986.20, y=24.00, z=-99263.74]
[19:12:24] [Server thread/WARN]: Wrong location! (-1062, -6204) should be (-1062, -6205), afg['Skeleton'/211715, l='swim3', x=-16988.09, y=41.00, z=-99261.55]
[19:12:24] [Server thread/WARN]: Wrong location! (-1062, -6205) should be (-1062, -6204), afg['Skeleton'/212803, l='swim3', x=-16983.49, y=40.00, z=-99269.13]
[19:12:37] [Server thread/WARN]: Wrong location! (1421, -847) should be (1422, -848), acf['Sheep'/224120, l='swim3', x=22749.50, y=69.00, z=-13544.31]
[19:13:14] [Server thread/WARN]: Wrong location! (-1057, -6205) should be (-1057, -6206), abn['Chicken'/288372, l='swim3', x=-16901.28, y=71.00, z=-99279.74]
[19:13:14] [Server thread/WARN]: Wrong location! (-1056, -6206) should be (-1057, -6206), abo['Cow'/288388, l='swim3', x=-16895.75, y=72.00, z=-99284.40]
[19:13:21] [Server thread/WARN]: Wrong location! (-1058, -6205) should be (-1058, -6204), afz['Villager'/292362, l='swim3', x=-16921.51, y=70.00, z=-99267.25]
[19:13:47] [Server thread/WARN]: Wrong location! (1416, -850) should be (1417, -850), abo['Cow'/351842, l='swim3', x=22671.98, y=67.00, z=-13599.94]
[19:13:47] [Server thread/WARN]: Wrong location! (1417, -851) should be (1417, -850), abo['Cow'/351843, l='swim3', x=22672.44, y=67.00, z=-13601.25]
[19:13:47] [Server thread/WARN]: Wrong location! (-1058, -6205) should be (-1059, -6205), afz['Villager'/357331, l='swim3', x=-16924.76, y=69.00, z=-99275.29]
[19:13:47] [Server thread/WARN]: Wrong location! (-1058, -6204) should be (-1059, -6205), ack['Iron Golem'/357334, l='swim3', x=-16925.35, y=68.00, z=-99259.30]
[19:13:47] [Server thread/WARN]: Wrong location! (-1058, -6204) should be (-1059, -6204), afz['Villager'/357338, l='swim3', x=-16927.30, y=69.00, z=-99260.40]
[19:13:47] [Server thread/WARN]: Wrong location! (-1059, -6205) should be (-1059, -6204), afz['Villager'/357339, l='swim3', x=-16935.56, y=66.00, z=-99269.01]
[19:13:47] [Server thread/WARN]: Wrong location! (-1059, -6205) should be (-1059, -6204), afz['Villager'/357344, l='swim3', x=-16941.50, y=66.00, z=-99267.62]
[19:13:47] [Server thread/WARN]: Wrong location! (-1058, -6204) should be (-1058, -6205), afz['Villager'/357346, l='swim3', x=-16913.82, y=69.00, z=-99258.80]
[19:13:48] [Server thread/WARN]: Wrong location! (-1059, -6207) should be (-1060, -6207), aci['Squid'/357447, l='swim3', x=-16943.10, y=52.04, z=-99308.91]
[19:13:48] [Server thread/WARN]: Wrong location! (-1059, -6205) should be (-1058, -6206), afz['Villager'/357673, l='swim3', x=-16931.58, y=67.00, z=-99275.56]
[19:13:48] [Server thread/WARN]: Wrong location! (-1060, -6200) should be (-1060, -6201), aft['Zombie'/359792, l='swim3', x=-16949.19, y=36.00, z=-99199.85]
[19:14:01] [Server thread/WARN]: Wrong location! (1430, -871) should be (1430, -870), abw['Pig'/375707, l='swim3', x=22887.35, y=66.00, z=-13923.88]
[19:14:29] [Server thread/WARN]: Wrong location! (-1059, -6204) should be (-1058, -6204), aea['Creeper'/441683, l='swim3', x=-16929.07, y=19.00, z=-99250.60]
[19:14:29] [Server thread/WARN]: Wrong location! (-1059, -6205) should be (-1058, -6204), ack['Iron Golem'/441688, l='swim3', x=-16933.94, y=66.00, z=-99268.70]
[19:14:29] [Server thread/WARN]: Wrong location! (-1053, -6205) should be (-1053, -6204), abp['Horse'/441693, l='swim3', x=-16838.87, y=72.00, z=-99268.30]
[19:14:29] [Server thread/WARN]: Wrong location! (-1053, -6205) should be (-1053, -6204), abp['Horse'/441694, l='swim3', x=-16842.32, y=72.00, z=-99266.72]
[19:14:41] [Server thread/WARN]: Wrong location! (-1052, -6200) should be (-1052, -6199), abn['Chicken'/446744, l='swim3', x=-16826.37, y=39.00, z=-99184.49]
[19:15:02] [Server thread/WARN]: Wrong location! (521, -140) should be (521, -141), aci['Squid'/493595, l='swim3', x=8337.25, y=50.15, z=-2239.80]
[19:15:02] [Server thread/WARN]: Wrong location! (515, -141) should be (516, -142), aci['Squid'/493627, l='swim3', x=8254.92, y=43.51, z=-2255.36]
[19:15:02] [Server thread/WARN]: Wrong location! (521, -143) should be (521, -142), aci['Squid'/494103, l='swim3', x=8339.76, y=48.44, z=-2274.92]
[19:15:03] [Server thread/WARN]: Wrong location! (521, -141) should be (520, -141), aci['Squid'/495135, l='swim3', x=8337.56, y=45.51, z=-2251.19]
[19:15:03] [Server thread/WARN]: Wrong location! (520, -141) should be (520, -142), aci['Squid'/495884, l='swim3', x=8323.66, y=51.18, z=-2254.44]
[19:15:03] [Server thread/WARN]: Wrong location! (516, -141) should be (517, -141), aci['Squid'/496719, l='swim3', x=8266.67, y=54.92, z=-2250.21]
[19:15:03] [Server thread/WARN]: Wrong location! (515, -142) should be (515, -141), aci['Squid'/497050, l='swim3', x=8249.97, y=46.26, z=-2258.38]
[19:15:03] [Server thread/WARN]: Wrong location! (515, -142) should be (515, -141), aci['Squid'/497051, l='swim3', x=8253.79, y=42.79, z=-2258.82]
[19:16:07] [Server thread/WARN]: Wrong location! (1437, -871) should be (1438, -871), afg['Skeleton'/592029, l='swim3', x=23000.50, y=40.00, z=-13926.89]
[19:18:15] [Server thread/WARN]: Wrong location! (518, -141) should be (517, -141), aci['Squid'/748463, l='swim3', x=8291.46, y=47.46, z=-2248.55]
[19:18:15] [Server thread/WARN]: Wrong location! (512, -142) should be (512, -141), aci['Squid'/749163, l='swim3', x=8203.60, y=51.17, z=-2258.88]
[19:21:01] [Server thread/WARN]: Wrong location! (1437, -870) should be (1438, -871), aea['Creeper'/957771, l='swim3', x=23007.45, y=15.00, z=-13918.63]
[19:21:01] [Server thread/WARN]: Wrong location! (1437, -871) should be (1438, -871), aea['Creeper'/957775, l='swim3', x=23006.95, y=50.00, z=-13930.09]
[19:21:34] [Server thread/WARN]: Wrong location! (-1053, -6204) should be (-1053, -6205), abp['Horse'/985758, l='swim3', x=-16839.99, y=72.00, z=-99263.38]
[19:22:18] [Server thread/WARN]: Wrong location! (365, -423) should be (365, -424), aci['Squid'/1026678, l='swim3', x=5847.94, y=49.14, z=-6767.99]
[19:22:18] [Server thread/WARN]: Wrong location! (363, -424) should be (363, -425), aci['Squid'/1029911, l='swim3', x=5815.50, y=61.18, z=-6783.67]
[19:22:18] [Server thread/WARN]: Wrong location! (363, -424) should be (363, -425), aci['Squid'/1029913, l='swim3', x=5810.81, y=58.81, z=-6781.15]
[19:22:18] [Server thread/WARN]: Wrong location! (361, -424) should be (362, -424), aci['Squid'/1031007, l='swim3', x=5791.47, y=56.42, z=-6777.73]
[19:22:18] [Server thread/WARN]: Wrong location! (363, -424) should be (362, -424), aci['Squid'/1031009, l='swim3', x=5810.05, y=54.25, z=-6772.62]
[19:22:18] [Server thread/WARN]: Wrong location! (362, -424) should be (363, -424), aci['Squid'/1031456, l='swim3', x=5807.23, y=60.36, z=-6782.94]
[19:22:18] [Server thread/WARN]: Wrong location! (363, -425) should be (363, -424), aci['Squid'/1031458, l='swim3', x=5821.37, y=62.36, z=-6784.16]
[19:22:47] [Server thread/WARN]: Wrong location! (-1057, -6206) should be (-1057, -6207), abw['Pig'/1072150, l='swim3', x=-16905.53, y=71.00, z=-99295.45]
[19:22:47] [Server thread/WARN]: Wrong location! (-1057, -6206) should be (-1057, -6207), abw['Pig'/1072152, l='swim3', x=-16898.07, y=71.00, z=-99291.81]
[19:22:50] [Server thread/WARN]: Wrong location! (-1062, -6203) should be (-1061, -6203), aci['Squid'/1074072, l='swim3', x=-16978.85, y=47.61, z=-99238.04]
[19:22:50] [Server thread/WARN]: Wrong location! (-1062, -6204) should be (-1061, -6203), aci['Squid'/1074073, l='swim3', x=-16980.07, y=47.36, z=-99249.53]
[19:22:50] [Server thread/WARN]: Wrong location! (-1061, -6204) should be (-1061, -6205), abw['Pig'/1074714, l='swim3', x=-16962.74, y=63.00, z=-99249.45]
[19:23:04] [Server thread/WARN]: Wrong location! (456, -393) should be (457, -393), aci['Squid'/1144153, l='swim3', x=7311.60, y=59.43, z=-6278.90]
[19:23:04] [Server thread/WARN]: Wrong location! (460, -392) should be (460, -393), aci['Squid'/1148001, l='swim3', x=7373.35, y=60.01, z=-6270.97]
[19:23:04] [Server thread/WARN]: Wrong location! (461, -392) should be (461, -393), aci['Squid'/1149985, l='swim3', x=7388.35, y=60.96, z=-6270.84]
[19:23:30] [Server thread/WARN]: Wrong location! (308, -557) should be (308, -556), afg['Skeleton'/1259032, l='swim3', x=4934.67, y=12.00, z=-8898.85]
[19:23:50] [Server thread/WARN]: Wrong location! (462, -388) should be (463, -388), aci['Squid'/1273252, l='swim3', x=7403.40, y=61.57, z=-6205.26]
[19:23:50] [Server thread/WARN]: Wrong location! (464, -388) should be (463, -388), aci['Squid'/1273253, l='swim3', x=7425.50, y=56.02, z=-6207.62]
[19:23:51] [Server thread/WARN]: Wrong location! (344, -410) should be (344, -409), aci['Squid'/1287258, l='swim3', x=5510.66, y=55.99, z=-6544.72]
[19:24:11] [Server thread/WARN]: Wrong location! (306, -560) should be (307, -560), aft['Zombie'/1322670, l='swim3', x=4911.54, y=40.00, z=-8948.93]
[19:24:37] [Server thread/WARN]: Wrong location! (293, -564) should be (294, -564), aci['Squid'/1337856, l='swim3', x=4703.40, y=48.04, z=-9011.46]
[19:24:37] [Server thread/WARN]: Wrong location! (295, -563) should be (295, -564), aci['Squid'/1339356, l='swim3', x=4722.41, y=49.63, z=-9005.88]

kumasasa 2014-07-31T19:25:30Z

@@unknown That's MC-2545

Anthony Martin 2014-08-01T00:31:48Z

I know that error is documented in MC-2545, and I clarified that there are no corrupt chunks involved here. I believe the server is trying to spawn mobs in unloaded chunks, not corrupt chunks. Prior to 14w30c, there was no indication that mobs were being spawned in unloaded chunks, so I believe it's new logging of old behavior.

Alex Berlin 2014-08-03T01:57:58Z

alexander- how was this exploited by players on your server to farm massive amounts of tnt? It would seem that this issue limits farming rather than boosts it.

Thijs Lacquet 2014-08-06T11:46:12Z

@Anthony Martin That has nothing to do with the bug reported here. Your log is showing that the server is trying to spawn mobs in CORRUPT chunks. The bug reported here has to do with the way the mobs are divided across the server.

galaxy_2alex 2014-10-25T19:10:38Z

Is this still a concern in the current Minecraft version 1.8.1 Prerelease 3 / Launcher version 1.5.3 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.

user-f2760 2017-02-14T15:11:44Z

Ticket resolved as incomplete, because no answer in a reasonable amount of time (1+ year), if it still happens, please update the ticket.

Elliot Wright 2020-11-17T13:55:37Z

This is still an issue (at least in 1.14.x, 1.15.x and 1.16.x), and has been for a long time. If you watch Minecraft YouTubers (e.g. HermitCraft) then you'll hear them talk a lot about how when other players are online they can't AFK at their mob farms because they don't get any spawns. They play on a Vanilla server with some datapacks, but this affects all Minecraft servers, except those who use Paper with per-player-mob-spawns turned on.

On the one hand, you can start to think the Vanilla behaviour here makes sense. Your join a brand new, empty server (i.e. new world), mob cap is 70 for monsters, they spawn around you - all is well. You move (far) away, and another player joins, the mob cap doubles, and mobs are spread fairly evenly. The problems come in when you start lighting places up, or doing things like creating mob farms. If one of those 2 players lit up all of the caves and surface around them, and no mobs could spawn around them at all then the mob cap would remain the same globally, and the other poor player would get all of the mobs spawning around them instead.

Mob farms are where I personally have the biggest issue with this, if you play on an active multiplayer server it just makes them completely useless. You need to find a time when nobody is online at all other than you for them to work.

Clearly, given that Paper have made a working solution for this that feels right when you play it, it means that Vanilla could also do this.

I think the logic would go something like this: mob caps behaviour remains the same, but the game tries to spawn <mob cap> / <players online> mobs around each player. Mobs shouldn't spawn too close to each other unless they spawn in packs up to a harder limit (i.e. so if you had a single-layer mob farm then you wouldn't get 70 mobs spawning on that one layer).

For now, I'll continue to play on a Paper server, but to be honest I'd much rather play on a Vanilla or possibly Fabric server, as Spigot and Paper modify a LOT of stuff about the game, and I'd rather have Vanilla behaviour - except for this - this is just a biggie!