Weekend Reading Notes

Session #1 Netflix's Distributed Computing Strategies: Optimistic Design for the Eventual Consistency Model

Good Netflix Case study on Cassandra for High Performance DB's

• In a master / slave configuration there is a interval for data sync
• Early 2000's reads were done on replicated databases 
• Repair option possible in cassandara
• MYSQL users - Facebook, Zappos, Symantec etc..
• FB replays logs across Slave systems 
• Remove Foreign keys to improve performance
• Netflix Cassandra cluster (1 Million writes / Reads worked successfully) - More reads link
• Benchmarking Cassandra Scalability on AWS - Over a million writes per second
• Pessimistic Design - High Consistency = High Latency, Performance issues 
• Optimistic Design - Trust Data Store, For 1% or edge cases have contingency plans
• Example, Amazon (Low Consistency, sometimes sell items not in inventory), Send a polite email, 10% credit for next purchase

Session #2 - How Python Scripts Power Drones

CS Concepts 

• Whats the difference between statically and dynamically typed languages?
• Explain several different CPU scheduling algorithms.

Good Programming Questions

• Given an array of integers, sort the array into a wave like array, namely a1 >= a2 <= a3 >= a4 <= a5

Good Solution Approach - Sort array first and swap pairs of numbers? So 7 6 5 4 3 2 1 becomes - 7 5 6 3 4 1 2

• Given an array of non-repeating, non-sorted, positive and negative integers, find 4 numbers in that array which satisfy the following equation: A1 + A2 + A3 = A4 
• Given a string determine which character appears the most and the number of times that character appeared.

Happy Learning!!!