Certain redstone cirtuits cause severe lag occasionally, to the 0 fps. For example simple redstone clock.
I've tested it in various versions of the game. The issue appears only in prerelease 7 and further up to release candidate 1 and including it. Prerelease 6 does not have such issue: the circuit causes fps to drop occasionally, to 25-30 from 60+, but not to 0-1. I'm attaching videos displaying freezes occuring in prerelease 7, in release candidate 1, and a video displaying absence of the bug in prerelease 6. Also this bug presists in both multi and singleplayer, also I tested it at least on 2 more different PCs and it persists there as well.Β
If needed I can provide additional info or run additional tests.
I have uploaded part of world where you can reproduce the issue, however I had to split archive to 4 parts because of file limit. You will need to download all 4 into same folder and extract it with 7-zip or winrar (or any archive extraction program that supports split rar archives). Just press the button on the floor few times or replace it with redstone torch and you will get some freezes. If you spawn somewhere else, teleport to -315 67 23
Related issues
is duplicated by
Attachments
Comments
migrated
galaxy_2alex
Thank you for your report!
However, this issue has been temporarily closed as Awaiting Response - this does not mean the report is not valid, we just need more information to verify it.
While the lag occurs, please run /debug start, wait a while and then run /debug stop in order to create a debug profile. Afterwards, run /debug report.
If you do not have the permission to run these commands, open your world to LAN and enable cheats. If you're on a server, make sure that you're a server operator in order to execute these commands.
Then, please attach the profile results found in [minecraft/debug/profile-results-<DATE>.txt|https://minecrafthopper.net/help/guides/finding-minecraft-data-folder], as well as the debug report found in [minecraft/debug/debug-report-<DATE>.zip|https://minecrafthopper.net/help/guides/finding-minecraft-data-folder] here.
Quick Links:
π Issue Guidelines β π Community Support β π§ Customer Support β βοΈ Feedback and Suggestions β π Game Wiki
π¬ Mojira Subreddit β π¬ Mojira Discord
migrated
Hello. I added debug results as you asked. However please note that because client is almost completely unresponsive during lag, I could only start debug before lag occurs and only could stop it after it was gone, so the report contains some time where there was no lag at all.
violine1101
Does this only happen in this precise area or also at any other locations?
migrated
So far I couldn't replicate it in the test world, and it's quite difficult to troubleshoot because this particular area has quite a lot of stuff - village, mob farm, large item moving setup. But I'm going to keep trying as well.
migrated
I think I found what exactly causes the problem - it's vertical redstone transmission tower.
Build tower out of glass or half slabs. Then start attaching redstone clock generators into it, attaching new one at the point where redstone signal of previous stops reaching. After building and enabling few of these fps will suddenly fall to single digit (I believe complete freeze in my world was because of a lot of stuff around). I've uploaded test.mp4 video that demonstates the issue and test.7z with copy of test world to try it.
Also the fact that destroying vertical transmission tower in copy of my world stopped issue from ocurring indicates that the problem lies somewhere in this area. Also this is completely client-side issue and does not affects TPS of internal server at all.Β
Once I got back to 1.16 prerelease 6, the problem was completely gone and I could not replicate it in that version. Something has changed since it, and it causes this problem.
migrated
Can confirm for 1.16 Release Candidate 1. It's the vertical transmission tower causing the lag.
migrated
Confirm for 1.16.1
migrated
Can confim for 20w27a
migrated
Ε’This may be the same bug affecting larger flying machines without redstone towers, not by the towers but the way they work by chaining updates forward.
See also: MC-192845
[Mojang] Panda, I have linked my test world .zip via Google Drive in the MC-192845 report along with the button co-ordinates to compare lag, sorry to mention it here but that one is still unassigned and I believe them to be the same issue, 1.15.2 thru 1.16 snapshot 4 fine but a little client lag, post snap 4 urgh client deadlock [Not Responding] I have 2 listed builds that do it, one for about 60 seconds the other to crash point.
It's bad.
Panda4994
Thank you for including your test world in its 1.15.2 state!
MC-192845 is indeed affected by the fix for this issue, however the lag in your test world still got worse compared to 1.15.2, so we will keep that one open.
The cause of the lag in the test world is light updates caused by all the blocks changing from blocking light to letting light though and back.
Prior to the 1.16 snapshots when more than 64 blocks in a chunk changed at once, the client would not recalculate the light and just trust data from the server which might or might not have matched the correct state (see MC-166260). Now the client will always calculate the light itself, which can be more expensive.
Panda4994