What probably should be facebook DB design

Question

I was just wondering how many db queries might facebook be issuing to render a user's home page. Does anybody have some idea on how the facebook DB is designed. I've heard it runs MySql and there are thousands of replica plus more memcache server than DB Servers.

Is the facebook data shard-ed?

If it is does it go to every shard and search for the latest update of my friend. In worst case if I've 100 friends and suppose facebook has 101 shards, there is a possibility that each of my friend is in a different shard. How might facebook be handling this?

I'll be highly grateful if somebody can provide me seom hints or pointers towards something like "How to Design a DB for Social Networking Website". I'm just curious!

Answer 1

Facebook is using LAMP structure. Facebook’s backend services are written in a variety of different programming languages including C++, Java, Python, and Erlang and they are used according to requirement. With LAMP Facebook uses some technologies ,to support large number of requests, like

1. Memcache - It is a memory caching system that is used to speed up dynamic database-driven websites (like Facebook) by caching data and objects in RAM to reduce reading time. Memcache is Facebook’s primary form of caching and helps alleviate the database load. Having a caching system allows Facebook to be as fast as it is at recalling your data.

2. Thrift (protocol) - It is a lightweight remote procedure call framework for scalable cross-language services development. Thrift supports C++, PHP, Python, Perl, Java, Ruby, Erlang, and others.

3. Cassandra (database) - It is a database management system designed to handle large amounts of data spread out across many servers.

4. HipHop for PHP - It is a source code transformer for PHP script code and was created to save server resources. HipHop transforms PHP source code into optimized C++. After doing this, it uses g++ to compile it to machine code.

If we go into more detail, then answer to this question go longer. We can understand more from following posts:

1. How Does Facebook Work?
2. Data Management, Facebook-style
3. Facebook database design?
4. Facebook wall's database structure
5. Facebook "like" data structure

Answer 2

At this website you find lots of details about those big internet companies and their technical structures:

http://highscalability.com/