[MC-236682] Large and continuous lag spikes sometimes occur when loading/reloading into a world in 21w37a

The Bug:

Large and continuous lag spikes sometimes occur when loading/reloading into a world in 21w37a.

This issue did not occur in 1.17.1. This may be quite difficult to reproduce as this does not happen all of the time.

Steps to Reproduce:

Create a new world in 21w37a.
Exit the world.
Join the world again.
→ ❌ Notice how large and continuous lag spikes sometimes occur when loading/reloading into a world in 21w37a.

Expected Behavior:

The expected behavior would be that no large and continuous lag spikes would sometimes occur when loading/reloading into a world in 21w37a.

Linked issues

Please note that this isn't the same as MC-236646. This issue (MC-236682) occurs even when not loading chunks.

Seems like the game is out of available memory (94% in your screenshot) and stalling to wait for the GC. Try allocating more RAM.

This might be a separate issue actually. The game is using more RAM than in 1.17.1.

@ampolive The game needing more RAM is not surprising, it has to hold more block data due to the extended height.

Adrian Östergård 2021-09-16T07:11:51Z

Please attach a performance profile by using the key combination F3+L in the game.

2 more comments

Also attached a profile.

Ceresjanin123 2021-09-17T13:11:21Z

This is a duplicate of MC-236665

anthony cicinelli 2021-09-23T16:19:41Z

This appears fixed in 21w38a

@unknown can you confirm this is fixed as well?

Hi @unknown. Yes, I'm also able to confirm that this issue has been fixed in 21w38a.