I’ve installed Grafana on an RASPI with a local mySQL-DB.
Everything runs fine.
Now i want to start with a new MySQL Connection.
This results in an error: “db query error: query failed - please inspect Grafana server log for details”
The user can open the db and select queries.
The file is: /var/log/grafana/grafana.log
But then i get the next error when i want to open this logfile: failed to open the file.
Logged in as admin.
But why can’t i open the file? Any ideas?
I’ve installed Grafana on an RASPI with a local mySQL-DB.
Everything runs fine.
Does this mean Grafana is using MySQL already?
Now i want to start with a new MySQL Connection.
Does this mean you are trying to add an extra connection, or is this the
first connection?
This results in an error:
Please tell us exactly what “this” is - in other words, what have you entered
into Grafana in order to get the error message?
“db query error: query failed - please inspect Grafana server log for
details”
The user can open the db and select queries.
Which user? How are you verifying this?
The file is: /var/log/grafana/grafana.log
But then i get the next error when i want to open this logfile: failed to
open the file. Logged in as admin.
But why can’t i open the file? Any ideas?
Please show us what command you are trying to use to open the file, and the
error message which results.
Additional helpful information:
Antony.
Thanks for your fast reply! 
Yes it was the first connection on DB-Grafana.
I was struggling around with the rights on this file. With a littly study i found a way to upgrade the rights and read the logfile. What a nightmare 
To the DB-Connection: My user phpadmin had the rights for the DB, but Grafana wanted a user for the controller. Now i used “pi” and everything is fine
Finally I can start with grafana and my dashboards finally deliver the first graphics.
Thanks!