My measures have no history?

[sbeexoo (sbeex)]

Hi, I discovered that if I use a point as a “Measurement” then openHAB let me open a graph supposed to show me the history of the value.

This is a great feature that I would like to use for humidity and temperature in my rooms.

By default my persistence module is: MapDB storing only the last state value

I would like to only keep track of some things for long term. Which persistence module should be used for that ?

Thank you for your guidance here.

EDIT:

I could find this answer OpenHAB 3: Item "Analyse" doesen't work - #5 by rlkoshak apparently I should use RRD4J as default for it to work.

However I don’t want to store all my items states using RRD4J it seems overkill for most of my data.

I guess I will have to do some filtering or is there a way to tell the analyze module to use RRD4J data?

[Udo_Hartmann]

You can setup which items shall be persisted an in which way.
For rrd4j, at minimum you’ll have to use everyMinute strategy, you can add everyChange to get more accurate data.

In openHAB up to OH3.x, you would have to setup via text file /etc/openhab/persistence/rrd4j.persist (default path for GNU/Linux) You can get a demo file here:

Persistence

(second java block)

In openHAB4.x you can use Main UI → Administration → Settings → (left Column) Persistence → rrd4j and add the items to be persisted.

If rrd4j.persist exists (and is valid), Main UI is read only for this feature (unlike other functions, which may work in coexistence via text and UI).

[rlkoshak (Rich Koshak)]

rrd4j is not the only other option. You can use pretty much any persistence engine for this except mapdb.

As @Udo_Hartmann mentioned, you have full control overv what gets saved to which persistence engine and when through the persistence config.

But I also want to mention, if your concern is size, rrd4j requires < 1MB per Item, forever. It’s a fixed sized database so it’s never going to take more than that.