Hello, I wanted to add an historic state for an item, that was newly created, but when using the blockly element for persist item state at a given time, this WARN pops up in the openhab.log: [ WARN ] [nce.extensions.PersistenceExtensions] - There is no modifiable persistence service registered wit…

Did you try to persist other items than number items? That will not work, as rrd4j can only store number items.

[image] poisonnuke: what does that mean an how can I modify/create old states of items with blockly? Or is it only possible with other means? Adding to what @Oliver2 correctly wrote, RRD4J can only store actual values.

I have a kWh meter item, so these are actual numbers. I just want to send 0 to a specific date in the past so that difference-last has something to compare to.

[image] poisonnuke: [ WARN ] [nce.extensions.PersistenceExtensions] - There is no modifiable persistence service registered with the id ‘rrd4j’ what does that mean an how can I modify/create old states of items with blockly? Or is it only possible with other means It means you cannot modify …

[image] mstormi: It also means you need to think of a different to accomplish whatever you want to compute. But why, is there no way? Ive read about some commands that are able to access past states in RRD4J and change them or even add new ones. Even though its round-robin, it should still h…

[image] poisonnuke: Ive read about some commands that are able to access past states in RRD4J and change them Then you’re wrong about that. [image] poisonnuke: But for that there must be a past value in the previous period. Many roads lead to Rome. As I already said, [image] mstor…

[image] mstormi: It also means you need to think of a different way to accomplish whatever you want to compute. and thats the reason Im asking here, because I dont know of any other way.

[image] poisonnuke: what does that mean an how can I modify/create old states of items with blockly? Or is it only possible with other means? Ultimately it’s you can’t do that with rrd4j. You’ll have to use some other database for this use case. I am pretty sure you can’t write new values ex…

[image] rlkoshak: Where have you read these? It’s more than just roud-robin. It’s also fixed size. An rrd4j database never grows. It accomplishes this by decimating older values. In order to do that decimation, it requires a fixed number of entries over a certain time period (that’s why everyMin…

[image] poisonnuke: Could someone point me to a good starting point where the current RRD4J implemention in the code is? I would like to check wether or not its really that easy. A simple community search should have given you the following, explaining how to modify a rrd database. Rrd4j: sm…

RRD4J - cannot modify historic item state

Setup, Configuration and Use Items & Sitemaps

hmerk (Hans-Jörg Merk) January 12, 2025, 10:52pm 11

A simple community search should have given you the following, explaining how to modify a rrd database.
Rrd4j: smoothen data and edit rrd-files - Add-ons / Persistence Services - openHAB Community