Ratio

For each time series in a set of time series, computes the ratio of that time series against the sum of all time series for the group matching the metric. For example, if you want to know the percentage of traffic each host is handling for a cluster in a data center, you can use the ratio to show that percentage over time. The output can be a percentage (e.g. 20.5) or a ratio (e.g. 0.205).

Fields for the ratio config include:

Name	Data Type	Required	Description	Default	Example
dataSource	String	Required	The TimeSeriesDataSource node ID to match and compute a ratio on.	null	m1
as	String	Required	The metric name to substitute for the output of the node.	null	host_traffic_ratio
asPercent	boolean	Optional	Whether or not to convert the ratio to a percentage (simply multyping it by 100).	false	true
infectiousNan	boolean	Optional	Whether or not NaNs from the source data should infect each timestamp when aggregating values. E.g. if one value out of 20 are NaN for a timestamp and this is true, the timestamp will return a NaN. If all values for the timestamp are NaN then the result will be NaN regardless.	false	true
interpolatorConfig	List	Required for now	A list of interpolator configs for the downsampler to deal with empty buckets.	null	See Interpolators

Example:

  {
      "start": "1h-ago",
      "executionGraph": [{
                      "id": "m1",
                      "type": "TimeSeriesDataSource",
                      "metric": {
                              "type": "MetricLiteral",
                              "metric": "sys.if.in"
                      }
              },
              {
                      "id": "ds1",
                      "type": "downsample",
                      "aggregator": "sum",
                      "interval": "1m",
                      "runAll": false,
                      "fill": true,
                      "interpolatorConfigs": [{
                              "dataType": "numeric",
                              "fillPolicy": "NAN",
                              "realFillPolicy": "NONE"
                      }],
                      "sources": ["m1"]
              },
              {
                              "id": "ratio",
                              "type":"ratio",
                          "dataSource":"m1",
                              "as":"colo_ratio",
                          "asPercentage":true,
                              "sources": ["ds1"]
                      }
      ]
  }

An implementation note: The node adds a Group By node to the execution graph that sums all time series for the given data source ID. It then replaces itself with an expression node that divides each time series with the group by result using a cross join. If `asPercentage` is set to true, an extra expression node is added to multiply the ratio by 100.