Recovering Item value on startup

Setup, Configuration and Use Items & Sitemaps
1

Hi,

I developed a rule, to measure my energy consumption. For this reason I created a number item, with contains the total energy consumption of the whole year.
I also created a date-time item, which contains the time, the rule run the last time to add the daily consumption to the item with the yearly consumption. I did that, because I want to prevent the rule of accidentally adding the daily consumption to the yearly consumption several times a day.

After restarting Openhab I noticed, that the value of the yearly consumption (number item) is recovered to the value before the restart automatically, but the value of the item with the last run timestamp (date time) is null.

I’m wondering, which kind of items are automatically restored the their values before a restart of openhab. Is there a documentation for this behavior?

Regards,
kuczerek.

2

Any Items persisted using the restoreOnStartup strategy will retain their value after a restart.

Consider using the MapDB service for this purpose.

3

OK, that gave me a hint. I was looking for the this information:

NOTE: rrd4j is for storing numerical data only. It cannot store complex data types. The supported item types are therefore only Switch (internally mapped to 0/1), Dimmer , Number , Contact (internally mapped to 0/1), Rollershutter and Color (only brightness component stored).

Found in:

Thanks.