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MC-89605

Toggling the {auto:0/1b} tag in Impulse command blocks with another Impulse command block causes buildup lag.

How to recreate:

Create a contraption like in the image below ('setup example'). Have the two impulse command blocks activate the adjacent one, whilst the chain blocks deactivate their origin impulse block. Also create a clock adding a score to any dummy player, and display that score on a visible scoreboard (for visual representation of lag). Make sure to activate the clock.

Once the clock is activated, set the 'redstone needed' to 'active' in one of the impulse blocks (doesn't matter which one). After activation, watch the test dummy score go up, but rapidly slow down in the rate of increase, until it comes to a full stop. When the score increase freezes, the game will start lagging FPS-wise, and will eventually freeze as well. Consequences of this will be that when the player relogs, the chunk resets to an older state before the 'redstone needed' button was set to 'active'.

By activating / deactivating I dont mean powering the impulse block, but switching the "auto" tag. This causes buildup lag.

Current discoveries:

  • Does not care about amount of RAM used (same outcome with 1/2/3GB

  • /gamerule logAdminCommands does not decrease nor stop this bug from happening.

  • Neither does /gamerule commandBlockOutput, nor /gamerule sendCommandFeedback

EDIT: Added crash report to attached files.

EDIT2: Rephrased title.

Attachments

Comments 12

Please force a crash by pressing F3 + C for 10 seconds while in-game and attach the crash report ([minecraft/crash-reports/crash-<DATE>-client.txt|http://hopper.minecraft.net/help/finding-minecraft-data-folder]) to this ticket.

Crash report added to attached files

Memory: 422727984 bytes (403 MB) / 1060372480 bytes (1011 MB) up to 1060372480 bytes (1011 MB)

You're running out of memory, assign more RAM to Minecraft, see MC-12949

The crash is from after I activated the contraption (meaning I force-crashed it when it started freezing). Do I take one before as well?

No, just assign more RAM.

2 more comments

Still happens in 15w45a.
Added new bug reports pre-activation and post-activation of the machine using 3GB.

Pre- and post-activation crashlog

After more investigation, I discovered that impulse command blocks activating other impulse command blocks using the 'auto:1b' tag causes lag. Using chain command blocks instead doesn't cause lag.

Is this still an issue in the latest snapshot 16w44a? If so please update the affected versions.

This is an automated comment on any open or reopened issue with out-of-date affected versions.

Is this still an issue in 1.13 or the current 1.14 snapshot?

bananenbroek4

(Unassigned)

Confirmed

Minecraft 15w39c, Minecraft 15w40a, Minecraft 15w40b, Minecraft 15w44b, Minecraft 15w45a, Minecraft 16w36a

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