Investigate choosing the right ranking mechanism for /stat/set collection APIs

[shifucun]

When query stat for a collection of places, now the latest data for each place is used (

mixer/internal/server/stat/stat_point.go

Line 321 in 1c4dd7f

if !ok || pointStat.Date < cohort.PlaceToLatestDate[place] {

) and they could be from different sources.

Another option is to get data from the highest ranked source, which might not have the latest data.

There are pros and cons for each option. Latest data could be of low quality (from wiki etc); Census decennial has 2020 data but only has 3 data points, so not good to be a general preferred source for time series.

[hareesh-ms]

Tracked in internal bug.