Extreme lag from decaying leaves

affects 18w32a

affects 1.13.1 pre1

This is most likely due to the new way that leaf decay is handled with the 'distance' tag, which gets updated for all connected leaves in a 7 block radius every time a log is broken.

affects 1.13.1

Kernel: Linux excession 4.18.0-2-amd64 #1 SMP Debian 4.18.10-2 (2018-11-02) x86_64 GNU/Linux

OS: Debian GNU/Linux testing (buster)

Java: 11.0.1 64bit

CPU: 8x Intel(R) Core(TM) i7-2700K CPU @ 3.50Ghz

Display: GeForce GTX 980 Ti/PCIe/SSE2

4.6.0 NVIDIA 390.87

Continues to be an issue in 18w46a (has been an issue since the 1.13 snapshots or earlier). I've also tried with Java 8 and the issue is there too. I have seen people playing the latest snapshot on Windows (10?) 64bit without any issues.

Also, this is not network lag/latency, this is a CPU spike causing a severe drop in framerate each time a log is broken and as the leaves decay.

also affects 19w04b

Confirmed for 19w06a

Confirmed for 19w14b

Confirmed for 1.14 Pre-Release 1

Confirmed for 1.14 Pre-Release 5

Can also confirm for 1.14 Pre Release 5, as well as many other lag spikes

•  Can confirm in 1.14 full release

Made this same post by accident, sorry. Loaded up the world several hours after and it works fine, isn't consistent with me.

I'd like to add to this by saying this has only been an issue with oak trees for me. Every other tree I'm able to break without experiencing a harsh lag spike. Every now and then I'll be able to cut down an oak tree without any spikes, but that's around one every 50 trees if that. Can also report that it has been very consistent with me, reloading the save does nothing and I've had the save for around a week now, have also created new saves and every time I experience the same issue.

I am having the same issue I assume. (Not super tech fancy so that's why I assume)

Specs: Ryzen 5 2600

GPU: Geforce GTX EVGA 1070Ti FTW2 icx edition

With 2 SSD and one HDD and minecraft and java are the only 2 things installed on one SSD (Did that to see if the other SSD was a problem and nope still having the same issue)

I haven't touched the advanced settings under the launch options except changed the allocated ram, as I have no need to mess with anything there. I have 4GB of ram allocated to minecraft alone and thats CLEARLY not my issue as I have changed it higher and lower. My FPS seems to stay the same though but I know Im stuttering because I can feel it as I mine the tree and move in a tiny circle at the same time AND sometimes you can literally see it lag. But maybe its so fast that the numbers on screen for my fps dont even have time to change and show me. It drops occasionally but not on all the stutters. Please fix : / as now all I do when I mine trees is focus on this because I know about it and it bugs me. In the mean time on windows 10 edition for PC this doesn't happen so I will be on there in stead until this is fixed for the Java edition.

After some testing I discovered that setting biome blending to no higher than 5x5 resulted in no more lag spikes (if not highly reduced spikes). I spoke to some of the guys on the OptiFine discord and after a bit of back and forth we settled on an explanation one of them gave..

"in older versions, leaves had 2 properties, each of which could be in 2 states. they could be player-placed or natural, and they could be checking for decay, or not checking. a block update would always set the "check for decay" state to true, and that was it. the next time the leaf got a random tick, if the leaf is checking for decay AND there are no logs nearby AND the leaf is natural (not player placed), then the leaf would decay, and cause block updates to its neighbors. the neighbors would then start checking for decay, and the process repeats, very slowly.

in 1.13 though, mojang added a new property to leaves: their distance to the nearest log. every time a leaf gets a block update, it waits for 1 game tick, and then checks for nearby logs and updates its distance accordingly. the important thing here though is that it gives out block updates during this process, so its neighbors will ALSO check for nearby logs only one tick later, and the process repeats very quickly.

what I suspect is happening is that mojang dumbly decided to re-render the sub-chunk every time a leaf changes its distance property. so suddenly breaking a single log will cause a huge number of nearby leaves to change their distance, which then creates equally many chunk re-renders, and finally, an even huger number of biome checks."

To summarize, mojang seems to have written horrendously poorly optimized code. Which OptiFine fixes.

Yea...im still getting into the whole PC minecraft stuff but I do know what optifine does etc. For the most oart at least. Only thing is, there isnt an optifine download available for 1.14 villager pillager update. And I have always had my biome thing at 5x5 never higher nor lower Ill try lowering it and sweeing what that does hope it fixes it until optifine puts out a 1.14 update. And if it doesnt fix it cant we just turn off checking for decay or something :/ I dont really care for sapplings... sure Ill loose apples but I dont NEED them.

Edit: It does seem like a Biome mix issue or whatever, instead of 5x5 I just turned it off and it was like little to almost gone still noticable if you paid any attention to it but if you didnt know about it and turned it off it would fee like the bug never existed. Hope it gets fixed soon even with it off its still annoying and to me personally because I know it exist its stupid.

A few observations from 1.14 while working with a very few number of trees on a small island in a deep ocean biome that originally generated without any trees:

• The issue occurs also when chopping OR growing trees, particularly noticeable when using bone meal.

• I am able to induce huge lag spikes (~9fps) in 1.14 by planting a bunch of saplings in a line and chopping them down once they've all grown.

• Biome blending has a definite impact, but turning it off does not completely remove issue. Lag is significantly worse with 15x15 blending though.

• Render distance doesn't appear to have any impact

• This happens even with single trees.

• Looking up while chopping the wood seems to make it slightly worse, but I'm not sure.

• Turning off smooth lighting dramatically reduces lag spikes.

Yea I am not turning off smooth lighting everything looks sooo stupid without that on :/ Still gonna be on windows 10 edition until this gets fixed. (If it ever does)

EDIT: Can confirm turning smooth lighting off makes it stop but then that makes the game look bad in my opinion as I use shaders and mods soooo smooth lighting is needed. Please fix mojang!

Can confirm for 1.14.1

Confirmed definately for 1.14.1 !!!

Still in 1.14.2-pre4

Can confirm for 1.14.3-pre2.

Harvesting leaves with shears also creates massive lag. I believe the root cause of the issue is the same.

Still in 1.14.4-pre6

Yup...still in 1.14.4 pre-6

I think MC-148095 is related to this. The lag is very similar, and could be caused by decaying or updating leaves.

Edit: removed my experiences with lighting updates, because they seem to have been fixed as of 1.14.4.

Biome blend option is causing massive frame drops, if over 5x5. Still there with lower settings, but less noticable. Off eliminates the spikes, but looks ugly between biomes. still in 19w40a and of course present in release 1.14.4

Still happening in 19w41a

Still happens somewhat in 19w45a.