Cassandra Migration Is Postponed

So in today's Links of the Day post we have three links that discuss Twitter's postponement of their migration from MySQL to Cassandra for storage of tweets. Now normally features, releases and technologies get postponed all the time. Under normal circumstances most would not even blink about this announcement. However, in this particular case you have two very hot topics Twitter and NoSQL in the limelight.

Unfortunately, the timing of Twitter's migrations plans could not have been at a worse time. They've struggled during the World Cup trying to keep the service up. They've had to resort to some extreme measures including slashing API calls for third party applications.

In the grand scheme of things this is probably more of a bump in the road. All new technologies go through this and I expect to see an announcement in the future that Twitter has fully migrated. Regardless, Twitter is still using Cassandra just for other features at the moment.

I've included a presentation that we've previously discussed here about Twitter using Cassandra.

Original Post: Scaling Twitter with Cassandra

Scaling Twitter with Cassandra

Let's paint a little picture about how it was at Twitter prior to Cassandra.

• Horizontal and vertically partitioned MySQL
• Memcached (rows, indexes and fragments
• Application Managed

This obviously had drawbacks such as:

• Many single points of failure
• Hardware Intensive
• Manpower Intensive
• Tight Coupling

The solution, Cassandra, the NoSQL data store originally developed by Facebook and given to the Apache Software Foundation. The presentation below is from Ryan King, a member of the Storage Team at Twitter. The presentation dives into details of how Cassandra solved the problems listed above. Enjoy!