[Bug]: Insane lag on combat

[Woltox]

Possible Fixes

Yes

Modpack Version

All the Mods 10-2.17.zip

What happened?

https://spark.lucko.me/zez8ZVPHPU

Around 50% of the times I engage combat im having lagspike causing me to take insane amount of dmg, often im shot 30+blocks away (from a normal zombie).

Have never had any issues on ATM 9, 8, 7
Have moved my from HDD to SSD to see if there was any issue but no..

latest.log

No response

Developer reports

No response

[SouDescolado]

I have the same problem.
I am hosting the server in a dedicated machine and playing on another machine.
No warnings being shown in the server, only have problems when mobs fight back. Can safely kill pigs, place blocks, or mine. Only combat causes spikes.

[Admorei]

Im hosting on my pc and have no issues but everyone else connecting to my server has severe problems when fighting mobs.
Am running 2.13.
Would be able to provide any logs or try things out if that helps.

[arlight1]

can confirm same issue is happening here...makes boss fights very annoying.

[arlight1]

I believe I figured out the cause in my particular case!!

I took off all armor and unequipped all items 1 by 1 since I noticed the lag went away without any tools and equipment. By process of elimination one particular artifact was causing a 2-3 second lag spike only some of the time I was being injured!

The item causing it was the Steadfast Spikes. My guess is it's doing some knockback resistance calculation periodically which is resulting in an unexpected value or result. After unequipping it, everything behaves as normal. Highly recommend the pack creators disable the item if possible for the time being because it appears to only happen in combat and affect the entire server's entities when they freeze up for that 2-3 seconds.

[SouDescolado]

I did have Steadfast Spikes equipped. Combat worked perfectly without it. Removing them removed the lag.
Wearing it back bought back the lag, so can confirm is something related with the Relic Steadfast Spikes

[arlight1]

Awesome, thanks for confirming!!

[Admorei]

I have just checked the files on my server no player has steadfast spikes equipped. I think the issue persits with other artifacts too ? Will test as soon as i can get other ppl Online

[SouDescolado]

@Admorei I do have a lot of other artifacts, including the cowboy hat, onion rings, bunny slippers and a belt. None of those have anything related to Knockback, as Arlight1 suggested might be the issue. Maybe there is another artifact that has Knockback?
I did have a piece of armor with knockback resistance, but it didnt cause any lag.

[Admorei]

Ok couldnt test yet but as far as we think My friend has lags as soon as I get hit a lot. I dont have the dire claws.
I never have lags but im also playing on the same pc the server is hosted on
We will now see if my friend has lags when getting hit whilst alone.
Later we can also test if its a artifact of mine.
Will post as soon as I know things.

[Admorei]

We could actually not reproduce the bug at all with withers in the mining dimension. None of us had lags this time. Last time we did them in the nether and it lagged. Were both not sure if we sapped any artifacts in that time but something is defently up with some of them.

[arlight1]

The Steadfast Spikes can also cause you to get yeeted 10s of blocks away when hit. My guess is the knockback calculation itself is bugged in some way:
https://www.reddit.com/r/allthemods/comments/1huslx2/why_do_i_get_sent_flying_on_almost_every_hit/