Youtube top k Videos

Requirements:

1. Show top k most viewed video within time frame 1 hours, day, 1 month, from given streams of views.
2. return only max 1000 videos
3. timeframe should be sliding window

Out of scope: No arbitrary starting point

NFR:

4. after how many min of video view, it should be calculated in top view. less than 1 min
5. 1-100 ms read latency
6. massive view
7. massive videos
8. Too many host should not be used to calculate top views
9. No approximates
10. response should be paginated

Capacity Estimates:

70B views per days

Views count: 70 * 10^9 / 86400 = 70 * 10^4 = 700K /sec ~ 1M views/ sec

youtube gets

1M video / day ~ 3.6B videos in 10 yr ~ 3.6 GB * (data needed for 1 video metadata) ~ 3.6GB * 8 byte ~ 30GB

API designs

GET /v1/top/views/count=1000 Request:

{
	"duration" : Min/hour/Day/All
	"maxCount" : 1000
}

User auth token in header response:

{
	"status" : success,
	"data" :
	[
		{
			"videoUrl" : "hjsabdajknd",
			"views" : 20
		}
	],
	"page" : {
		"start" : "",
		"end" : ""
	}
	
}

Save View count inout: videoId