Why is my datapack so laggy?

[jeanid]

https://www.planetminecraft.com/data-pack/aceplante-s-rl-megapack-for-1-17/

For every single function I have added so far, I have been careful to add tag checks. For example, if I want to replace the held item of skeletons, I will only run that command at skeletons without the tag, then add it after so it doesn't run again.

So I am not sure why I am experiencing lag since as far as I can tell, everything is written as efficiently as possible. I tried debug but I do not seem to be getting a file as google claims I should.

I guess my question is what are some of the reasons it might be laggy? Is there a way I can find out what part of it specifically is causing the lag?

[jonetta]

There are many many reasons why a datapack may be laggy, and it is hard to diagnose the issue(s) without knowing what it does. But, here are some common reasons that I can list off the top of my head:

• Too many entities (e.g. using too many armorstands)
• High usage of heavy entity selectors (e.g. using @e a high amount of times)
• NBT (reading, writing, or accessing entity NBT data is extremely laggy. Like execute if entity @e[nbt=...])
• Large clone/fill commands
• Recursive functions, or in general, too many commands per tick (we're talking hundreds of thousands)