URL Shortening Service

Use Cases

1, shortening:take a URL = = return a much shorter URL

2, redirection:take a short url = = Redirect to the original URL

3, Custom url:http://goo.gl/trump2016

4, High availability

5, Analytics:

6, Automatic link removal

7, Manual link removal:e.g. porngraphy

8, UI vs. API, see HTTP://GOO.GL

Constraints:

Make some guess about the volume

1, new URLs per month:100 million = because Twitter daily tweets:

2, request per MONTH:1 billion =

3, 10% for shortening and 90% for redirection

4, Requests per second:400+ (40:shortens, 360:redirects)

5, Bytes per URL

6, 6 bytes per hash

Abstract Design:

1, Application service layer-services the requests

* Shortening Service

* Redirection Service

2, Data storage layer-keeps track of the Hash<->url mapping

* Acts like a big hash table

Bottlenecks:

1, Traffic-how Much, estimation, probably not the problem

2, data volume-quickly look up and insertion

3, how to split (scale)

URL Shortening Service