This would be my suggestion for a tutorial (@vzorglub, @PtrO comments are welcome). I will publish that in seperate thread afterwards:
HowTo: Changing values in a rrd4j database.
Note: Due to the setup of rrd4j databases a wrong value saved in archive 1 will also affect corresponding values in further archives. The way the other archives are effected depends on the consolidation function used. One should consider the check/update all archives when trying to remove a false value.
In order not to work on the database in question while it is written to openHAB should be stopped.
The file “rrd4j-2.1.1.jar” which is used by openHAB is needed. If you are running oenHAB on a headless raspberry, you should copy the .jar and the the .rrd file to another system that has Java installed.
Having both (the .jar and the .rrd) in the same directory the rrdInspector is started on the console with:
On windows the console has to be started as Adminstrator!
java -cp rrd4j-2.1.1.jar org.rrd4j.inspector.RrdInspector
Select your .rrd file and open the Archive for editing.
Change all false values, finding the values is easy since DateTime is given in a readable format.
Close the inspector.
Copy the changed .rrd back to your openHAB system and restart openHAB.