"Flat graph" for rrd4j in OH 3.0

Add-ons Persistence Services
1

For some Items graphs generated based on rrd4j are “flat”, e.g.

image
image1234×556 20.4 KB

I observe the following:

.items:
Number SpeedtestResultDown “Downlink [%.2f Mbit/s]” (gSpeedtest)

openhab.log:
2020-11-03 10:45:02.327 [DEBUG] [g.openhab.persistence.rrd4j.internal.RRD4jPersistenceService] - Stored ‘SpeedtestResultDown’ with state ‘821.00481118472’ in rrd4j database
2020-11-03 10:45:22.849 [DEBUG] [g.openhab.persistence.rrd4j.internal.RRD4jPersistenceService] - Stored ‘SpeedtestResultDown’ with state ‘821.00481118472 Mbit/s’ in rrd4j database (again)
2020-11-03 10:45:22.850 [DEBUG] [g.openhab.persistence.rrd4j.internal.RRD4jPersistenceService] - Stored ‘SpeedtestResultDown’ with state ‘646.5112701904’ in rrd4j database
2020-11-03 10:46:01.800 [DEBUG] [g.openhab.persistence.rrd4j.internal.RRD4jPersistenceService] - Stored ‘SpeedtestResultDown’ with state ‘646.5112701904 Mbit/s’ in rrd4j database (again)

I have wiped the .rrd4j files as well. It seems that the Item state is stored twice in the database, once with and once without the unit. I am also puzzled by the timings (it is EveryChange, EveryMinute as policy)

What is causing the flat charts?

K

2

Are you running milestone 2 ?

3

3.0.0-SNAPSHOT - Build #1995

I started digging, and maybe this is a change compared to 2.x, but I noticed that rrd4j is now storing UoM, instead of the raw values.

4

There were changes very recently in persistence and chart.
Charts started to work for me with snapshot 2004.
It should be ok in released milestone 2 too,