I think this is a bug in the rollup job, I can't plot reliable data using the rolled up indice because I can't get metrics average, only the sum. I'm using ES 7.4.0 and I'm specifically trying to make visualizations on kubernetes metricbeat data.
In this example, for instance, the memory usage average in this period is clearly 24mb and the sum is 741mb.
I get the same thing when I query the indice via REST:
$ curl https://<my-instance-ip>:9200/rollup-metricbeat/_search?size=1 -d '{"query":{"bool":{"filter":[{"range":{"kubernetes.pod.memory.usage.bytes.value_count.value":{"gt":0}}}]}}}' -H 'Authorization: Basic <my-token>' -H 'Content-type:application/json' | jq . | grep kubernetes.pod.memory.usage.bytes
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 11017 100 10911 100 106 26355 256 --:--:-- --:--:-- --:--:-- 26546
"kubernetes.pod.memory.usage.bytes.avg.value": 659943424,
"kubernetes.pod.memory.usage.bytes.max.value": 22036480,
"kubernetes.pod.memory.usage.bytes.value_count.value": 30,
"kubernetes.pod.memory.usage.bytes.min.value": 21934080,
"kubernetes.pod.memory.usage.bytes.sum.value": 659943424,
"kubernetes.pod.memory.usage.bytes.avg._count": 30,