1.
Reactive Manifesto
Developing Real-time Leaderboards
Binoy Shah
Technical Architect
Washington Post (Games)

2.
What is The Reactive Manifesto
http://www.reactivemanifesto.org/
Strive to be:
 Responsive
 Resilient
 Elastic
 Asynchronous

3.
 Philosophy: Convention over configuration
 Lightweight & Stateless
 Asynchronous & Non-blocking
 Message Driven [Actor based core framework]
 Resilient & Ops - Friendly
 Write code in Java and/or Scala
 Integrates well with Spring [OMG!!]
 Simple API
Play Framework

4.
 Realtime Game play & Leaderboards
 Millions of players
 Millions of Player scores x 1000's of Games
 Individual Player Rank [Dense Rank]
 Various Leaderboard rankings
• Per quiz
• Per category
• Global
Leaderboards

5.
Leaderboards – Dense Ranking

6.
Leaderboards - Initial Performance
RDBMS Performance for calculating player Dense rank
# of Player Scores Response Times (ms)
Oracle
Response Times (ms)
MySQL
User Experience
500,000 720 690
1,000,000 3454 3645
10,000,000
7662 7731
30,000,000
45,000 43,000
So are we doomed??

7.
Our hero…
Redis NoSQL Server

8.
Leaderboards - Solution
What is Redis?
 REmote DIctionary Server
 Open source (http://redis.io) since 2009
 Advanced in-memory key-value data-structure server

9.
Leaderboards - Solution
Available in-memory data structure in Redis:
 Hashes 
 List
 Sets
 Sorted Sets 
 Key Value

10.
Leaderboards – DB vs Redis
Load Test 30 million scores, 100k players, 100 leaderboards

11.
Leaderboards - Stack
Leaderboards AWS Stack

12.
Leaderboards…The Tech
Leading edge technology stack:
• Scala
• Java 8
• Play Framework
• Redis 3.0 NoSql DB
• JSON ( RESTful APIs )
• AngularJS
• Bootstrap ( JS Library
• Oracle 11g

13.
Leaderboards…The Tech
Leaderboard Stack [ Deployment Architecture ]

14.
Leaderboards – Live and Kicking !!
 Introduced for 'Politics & Pints' section articles
 Switched on as default feature of all Quiz games
 Logged in players can view participate and view
Leaderboards

15.
Key Takeaways
Design for simplicity
 Simplicity is key to being responsive
Develop iteratively and incrementally
 Development process is responsive, it can scale well to changing requirements
Optimize your application in phases
Load test application with worst case scenario in mind
 Forges path for scaling and being more elastic
Stress test your application
 Shows you bottlenecks in the system and help in optimizing the bottleneck

16.
Questions