Improving InfluxDB Sensor Data Queries
I now understand why Grafana built the initial query with
GROUP BY time($__interval). With a hard-coded value in
time(), every single point is
displayed on the graph, regardless of the zoom level. The
variable scales this value based on the time period displayed.
Initially, this did not work for me, and Grafana just drew seemingly random points when using any view besides "last 6 hours." This turned out to be because the default value for "min time interval" was not set (or was incorrect). Seting it to "10s" (which is the collectd poll interval) corrected this issue as well.