I have a question on how the persistence service works.
I have defined RRD4J as the default service and I have the strategy set to every change, every update, every minute.
My items are updated via MQTT every 10 seconds and I can use the persistence service in rules to check for frequency of saved states and it is right on, 6 data points per minute.
When I use the API to download the persisted data I only get one datum point every minute no matter how far back the starting time is, I only look back 1 day.
Is this how it is supposed to work?, why aren’t the 10 second saves downloaded?
rrd4j decimates the data as the data ages. This is how it manages to keep it’s size the same no matter how old the data gets. How this is done and at what age the data gets decimated is all in the rrd4j docs. But ultimately, if you want the data to remain pristine and unaltered, you need to use a DB other than rrd4j.
The reason why you are getting a result only every minute is because, for number values:
