[Infra UI] Make interval in Metrics Explorer configurable

[kaiyan-sheng]

When testing Metricbeat rds metricset using Metrics Explorer, we realized instead of showing lines in the graph, it's showing data as individual dots:

But if displaying data in longer time range, then it shows lines instead of dots:

For rds metricset, metrics are reported every 1 minute. We suspect the bucket size Metrics Explorer uses is smaller than 1min. So when querying data, it gets empty data points and that causes the graph to be with individual dots.

[kaiyan-sheng]

Possible solution is to add period into metrics that reported by Metricbeat so this value can be used by the interval for Metrics Explorer: elastic/beats#12616

[kaiyan-sheng]

cc: @sorantis @exekias and @simianhacker

[elasticmachine]

Pinging @elastic/infra-logs-ui

[exekias]

I wonder if this could be fixed by only considering it a gap when time difference is > 5 mins? We get doc_count for each bucket on the responses, so differentiating empty buckets from 0 and discarding them should be doable.

[simianhacker]

Since we agreed to tie Metrics Explorer to ECS we should use period if and when it becomes available. @Dimitri-Mazmanov From a product perspective, do we want to give the user a way to override the interval in the new chart configure UI?

[sorantis]

ignoring zube
@simianhacker, I think we shouldn't make the interval configurable in Metrics Explorer so long as we correctly show a graph using the period value exposed by Metricbeat. The users already have this option in TSVB if they choose to further customize the graph.

[simianhacker]

I'm going to close this issue, if we feel like it's something we want to consider in the future then we can re-open it.

[roncohen]

is there a way to just force it to connect the dots until period arrives?

[simianhacker]

@roncohen If we did this, I would add it to the chart "customize" menu as "Ignore gaps & connect points" (or something that conveys the same message) since that's really what we will be doing. The caveat to "connecting the dots" is that it won't work for any of the rates unless there are at least 2 points next to each other in the raw data. Those two points will be required to calculate the derivative, the points from the derivative will be connected. Also keep in mind when we link to the TSVB charts, they will NOT connect the dots since there ins't away to tell TSVB to the ignore gaps.

@sorantis @roncohen If we decide to move forward with this, we should create a new issue.