OH is going to have to do something with every message published to the topics it subscribes to. You will not be saving any CPU or memory in any way. In fact, to reduce the number of updates to the Items you will increase the amount of CPU and memory.
If it’s really just the Item changes you really care about reducing you can:
- in OH 4.2 you can use one of the
debouneprofiles - in OH 4.2 you can use the round profile to round the values before the Item is updated which will reduce the changes
- in OH 4.2 and earlier versions you can use Filter Profile to require the change to be above a certain amount before passing it through
Note though that except for debounce, all of these reduce the number of changes the Item goes through but do not reduce the number of updates made to the Item. But by default events.log doesn’t include updates so there’s that. For sensors you usually want to trigger on changes anyway so the fact that the Item is updating at the same rate but changing less frequently should be sufficient.
For this concern see How to watch and look through logging. No matter how full logs are they are never “useless”.