No and yes. You can have as many persistence add-ons installed as you want. I use InfluxDB for charting and MapDB for restoreOnStartup.
Yes. All of the Persistence add-ons are 1.x version add-ons. If it’s listed in PaperUI, it is the latest version of that add-on for that version of OH.
Or defined through PaperUI.
It has other uses too. For example, if you have an Item that you only ever need the lastUpdate time, MapDB is a good choice.
It doesn’t always make sense to restore all Items on startup. Sometimes it is better to allow an Item to remain NULL rather than to populate it with stale and possibly incorrect data. Other times it is better to recalculate the value during the System started Rule rather than restore some old and possibly incorrect value.
It all depends on personal preference and your use case. RRD4J is a great database to choose for numeric data where it is OH that the precision of the values stored can degrade a bit as the data gets older. But in exchange for the data becoming less precise as it ages you get a database that never grows larger no matter how much data you store in it.
InfluxDB, MariaDB, MongoDB, etc are great choices for exposing historic data to external tools or for charting. Which one to choose is largely a matter of preference and compatibility with other tools you want to use with the data (e.g. Grafana).
No, it’s still valid except for one thing. Grafana doesn’t really support generation of static images any longer. Everything else is valid.
See InfluxDB+Grafana persistence and graphing
Hmmm. I wonder if it is expecting a Group instead of a single Item. Most of the time we have more than one Item we want on the same chart and to do that we use a Group containing all the Items you want to chart. Maybe support for charting a single Item is broken?
VSC uses OH itself to check the code so you should see the same error in both places. It’s the same parsing code that is creating the error.