In our IoT use case, we are leveraging MongoDB’s time series functionality. Due to high write volume, we need to adjust the timeseries.granularity and bucketMaxSpanSeconds parameters to manage the write load. However, after increasing the bucketMaxSpanSeconds, we need to run the system for several days to observe stability. If the value is set too high, MongoDB does not support decreasing the bucketing value, and we are forced to create a new collection instead.

It would greatly simplify our testing process and increase flexibility in adapting to business changes if MongoDB allowed the decrease of bucketMaxSpanSeconds after it has been increased.