Mysql was no longer suitable for Twitter's large scale needs due to self joins becoming prohibitively expensive as the number of users grew to 106 million. Cassandra, a distributed database management system developed at Facebook, was better suited as it allowed for distributed storage and handled Twitter's social graph and high write volumes. Twitter's request flow involves distributing load balancing between FlockDB, Mysql, Memcached and Cassandra to improve performance and scalability.

1. @kirai
www.twinavi.jp

2. Mysql Cassandra

3. 106.000.000 Twitter.com
Mysql

4. 2009
• 1358%

5. SNS RDBMS
• SNS
• N X N relationships, social graph

6. Mysql
• Self Join
• 106.000.000 X 106.000.000 = ???
• Tweets Alter Table....
•

7. FlockDB
• DBMS Social Graph
• Distributed
• Twitter
• Open Source
• http://github.com/twitter/flockdb

9. Cassandra
• Facebook
• MapReduce Distributed storage solution
•
• Apache Open Source Level 1 project
• http://cassandra.apache.org

10. Mysql Cassandra
Mysql
Requests
STEP .-Cassandra Request
STEP 2.- Log
STEP 3.- Cassan
STEP 4.- STEP1 dra

11. Mysql Cassandra
Mysql
Requests
STEP .-Cassandra Request
STEP 2.- Log
STEP 3.- Cassan
STEP 4.- STEP1 dra

12. Twitter.com Request Flow
FlockDb
Gizzard
Mysql
106.00
0.000 Apache Rails
Load Memcac
mod_prox (Unicor
Balancers hed
y n)
Cassan
dra
Kestrel

13. Twitter.com Request Flow
FlockDb
Gizzard
106.00
0.000 Apache Rails
Load Memcac Cassan
mod_prox (Unicor
Balancers hed dra
y n)
Kestrel

16. http://dev.twitter.com/
status

17. http://twitter.com/about/
opensource