Empty buckets are not anchored on null for line charts

[jrunu]

Line charts that plot sparse aggregated data do not anchor empty buckets at null.

The example is grouped over time and event type, with an event count as aggregation metric.

Expected Behavior

Empty buckets have an aggregation count of zero, leading to a chart which can be adequately used for recognizing and comparing trend lines, even on sparse data.

Your Environment

• Graylog Version: Graylog 5.2.3

[fvjb]

Same here; aggregating Loglevel (Windows: error | warning | information); datapoints with zero-value do not appear as for example on Feb 2nd