Databases Used In Facebook

By: Chris Hayes

FacebookToday, Facebook is the most commonly used social

networking site for people to connect with one another online.

People of all ages use Facebook, and the uses for the site are staying connected with friends and family as well as meet new people with the addition of uploading pictures, videos and statuses to let people know how you are doing.

DatabasesA database is a structured set of data held in a

computer, one that is accessible in various ways and it manages data to allow fast storage and retrieval of that data.

There are many different databases within Facebook that make all its unique features possible.

There are close to half a billion active users, five hundred-seventy page views monthly, three billion photos uploaded per month, more than 25 billion pieces of content such as status updates, comments, etc. and over 30,000 servers.

Facebook uses databases such as MySQL, Memcached, Haystack, Cassandra, Hadoop and Hive, and scribe that keep the site up and running smoothly.

MySQLMySQL is an open source relational database

management system.Facebook uses MySQL primarily as a key-value store in

which its data is randomly distributed across a large set of logical occurrences.

The MySQL database is also used for structured data storages for wall posts, statuses, user information and so on.

MemcachedMemcached is a popular software within the

internet and it is known as a distributed memory chasing system.

Facebook uses Memcached as a caching layer between the web servers and MySQL servers.

Facebook runs thousands of Memcached servers with tens of terabytes of cached data at any one point in time.

HaystackHaystack is a high performance storage and retrieval

system for photos used by Facebook.Haystack is an object store so it does not necessarily

mean that it has to store any photos.Haystack is one of the busiest databases used in

Facebook because There are typically twenty billion photos uploaded to Facebook that are stored in four different resolutions resulting in the production of eighty billion photos which Haystack has to work on.

CassandraNo, Cassandra is the not the hot blonde that uses

her phone during class while you creepily stare at her the whole time.

It is a distributed storage system that tends to have no point of failure.

It has been made an open source database that Facebook uses for its Inbox search.

Hadoop and HiveHadoop and Hive are one database but they are

separate in terms of their functions. Hadoop is an open source map-reduce implementation

that makes it possible for websites to perform calculations on massive amounts of data.

Facebook uses Hadoop for data analysis which is important to Facebook’s duties because Facebook controls massive amounts of data.

Hive actually originated from Facebook and is used by Facebook to make it possible to use SQL queries against Hadoop, making Facebook easier for its active users to use.

ScribeScribe is a flexible logging system that Facebook

uses for a multitude of purposes internally.It’s been built to be able to handle logging at the

scale of Facebook, and automatically handles new logging categories as they show up.

Wrap-UpIt is databases like these that keeps it up and

running smoothly making it possible for Facebook to have up to half a billion active users. It is a lot of data entering Facebook from all these users, so Facebook has to make sure their databases are functioning properly in order to fulfill daily functions for the site.

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