OH3.1 Persistence RRD4J. Data not for manually created Items


I use OH 3.1 staple version (openhabian).

I will add from the GUI a new Item (Type: Number) and link this with a Channel.
The Item works fine and I get all data, but if I click on the Item value and check this on the graph then is here no data.

All other auto created persistence (create from Model > Create Points from Thing) works fine.
On the settings > persistence is RRD4J as default enabled.

I’ve delete the Item and create a new Item but the same behavior.

Persistence only selects what to persist at system or service startup.

I believe that if you have a default policy for persistence service set then newly created items should inherit that settings. If you have a selective persistence only for some items then you will get result you described.

Thanks. Can I create the persistence rules also from the GUI or is this only as code (textfile) possible?
Is somewhere documented the default rule as reference?

Perhaps in the future this will be possible in the GUI, but for now you’ll need to create a text file called rrd4j.persist. Note that it’s 4j, not j4 as in your topic title (I’ve made the same typo before).

The default is to persist every change to every item and restore on startup. The persistence docs include an example of a persistence file, but it doesn’t show the default (since the default doesn’t require any configuration).

I made some proof of concept work which is aimed towards this case. I took an approach to use item metadata instead of persistence files.
It is doable, however usage of persistence files has an advantage of defining policies for multiple items at once.
What could be a helpful here is making each persistence service defaults configurable. In fact there are no reasons why this could not be managed through UI.

Thank you very much all your posts, solutions and recommendations.
It was very helpful!

I hope that the config rules for persistence comes someday in the GUI.

Is this possible to set a default strategie for all Items (also for new created Items).
I see in the docs only to reference to existing Items.

Can I check and view the rrd4j DB and the values?

IMHO you can’t. OH3 uses a default strategy for all items as long as you don’t set an strategy., changing this strategy is not possible

Using the API Explorer you can check all database entries.

Last question.

I see now the values from the persistence DB e.g. Item “eSmartMeterGesamtleistung”.

But if I open this Item then I see no values in OH.