There's probably no particular reason for it. Just that it wasn't needed so far.

I don't quite understand which API's you need exactly? Do I get it right you want UserCountry.getNumberOfDistinctContinents and UserCountry. getNumberOfDistinctRegions? You could probably always request all Continents or all regions with filter_limit=-1 and then count the number of entries in the result.

Right, I am get all continents or city, then calculates the number of items to obtain the total number of, but such speed is not good.

So I want to have a method like UserCountry.getNumberOfDistinctCountries can be obtained directly from the count

True this is surely not perfect. I will adjust the title of the issue.

I recently thought of actually deprecating the getNumberOfDistinctCountries method at some point but on the other side we could also add more such API methods also for other APIs.

When we work on the new archiver in #7470 we could actually even archive such metrics automatically for all reports, and eventually maybe even add such API methods automatically as well.

When we work on the new archiver in #7470 we could actually even archive such metrics automatically for all reports, and eventually maybe even add such API methods automatically as well.

+1

Such report metadata could be returned by the Metadata API reports yet without requiring to load the full processed report.