Commands such as /test pos search within a range of up to 200 blocks (plus a duplicate range of 15 blocks), meaning a server that runs this command without a nearby test instance block will be very slow. This is because the command checks block states in an non-optimal manner.
The effect on the game is that it's very easy to slow down and eventually crash a server by putting /execute as @p run test pos x in a repeating command block.
This issue could be mitigated by using the Chunk#forEachBlockMatchingPredicate method, which should be a lot more efficient as it checks the palette of chunks rather than scanning the chunk's block states. It all goes full circle 😃
Thank you for your report!
After consideration, the issue is being closed as Won't Fix.
Please note that this is not the same as Working as Intended, as this bug report correctly describes behavior in the game that might not be the intended or desirable behavior, but it will not be fixed right now. Sometimes, this is because the issue reported is minor and/or impossible to change without large architectural changes to the code base.
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