Direct answer
Repeating commands can be expensive when they scan large entity sets, run nested execute chains or modify many blocks every tick.
How to check it
- Identify which command blocks are always active and record their exact commands, repeat/chain mode and affected dimensions.
- Compare spark profiles before and after a short, controlled pause of a suspicious command system on a staging copy.
- Look for broad selectors such as
@ewithout filters and repeated searches over unloaded or distant areas.
Example: A repeating selector running every tick against every loaded entity should be narrowed before you replace the entire adventure-map command system. Count matched entities and execution frequency.
What to change
Limit selectors to a nearby radius or tagged targets where correct, and trigger the action only when the gameplay event requires it. Move large batch operations to an explicit maintenance procedure rather than every tick.
Software and version notes
enable-command-block in server.properties enables or disables command blocks globally; changing it may break adventure maps. Commands differ by Minecraft version, so validate selectors in the test world.
Verify the result
Measure MSPT with the commands active and paused, then confirm scoreboards, maps and quests still update correctly.