Non persistent chart of last 30 minutes

Setup, Configuration and Use Beginners
1

Hello,

I’m quite new to Openhab, but i made already a nice overview in BasicUI.
I have Node Red as a rule engine on a seperate RPI. There i used the dashboard but i prefer to switch completely to OpenHab.
Now, i want to add a small chart, of the last 30 minutes, refreshed every 30 seconds.

When i read about chart, i see you need persistence. This is not what i want… First, the SD card will wear out, but also i don’t need historical data. When the RPI would restart, i don’t care i loose the values. (It’s just for having an impression that a control is doing well)
Does something like this exists? (or can i link to the chart in NodeRed?)

already thanks!

  • Platform information:
    • Hardware: RPI
    • OS: Openhabian
  • Rule Engine: Node Red on seperate RPI.
2

That’s what you need or how would openHAB “remember” the last 1/2 hour?

No

You can try creating a webview sitemap element pointing to the chart

3

I thought something of remembering it inside the chart; ‘in the work memory’ of openhab.

OK

Thanks, i’ll try this.

4

Both Apache Derby and H2 can be run as in memory databases. Both are supported by the jdbc persistence service. However I don’t know if it actually will work or how you should configure it. But theoretically it should be possible.

5

Why not use a database that is able to store exactly the data need. Rrd4j can be configured to save data in minute steps for the last 30 minutes, it will never grow.

1 Like
6

does somebody use Apache Derby or H2 as in memory database with openhab or know how to configure ? I have a similar use case lik @KoenH

Thanks in advance Lars