I am collecting data from a Proxmox host into an InfluxDB datasource. This datasource is used to power a Grafana dashboard. Data is collected as it should, but I have a problem plotting the CPU usage.
I have figured out that the data that is sent concerning the CPU is sent as jiffies, so I figured that;
System / System + User + Idle = Percentage System CPU Usage
I then have to take a mean of all those values to get the mean System CPU usage for the last minute. Here is where i run into a problem. The InfluxDB documentation states
The use of mathematical operators inside of function calls is currently unsupported.
as can be found here InfluxDB documentation
My question is if there is a workaround for this so I can calculate the mean of a sum.
There is a way to do this with InfluxDB, but its a two step process.
SELECT System / (System + User + Idle) AS avg
INTO "sys_cpu" FROM "my_measurement"
Then simply issue a query
SELECT mean(value) FROM "sys_cpu" GROUP BY time(<interval>)
Its kind of messy, but should work.