Distributed Databases and Distributed Systems

Course topics

Module 1.  Why Distributed DB and Distributed Systems? Remote Procedure Call

• Network socket
• RPC
• Sync/Async call
• Messaging
• gRPC

RDBMS

• App architecture
• Business transaction vs System transaction. Distributed transactions
• ACID – properties of database transactions
• Transaction isolation levels
• Pessimistic vs optimistic locking. Lost update problem

Distributed transactions

• 2PC protocol
• 3PC protocol

Module 2.  NoSQL

• RDBMS problems. ORM (Object-relational mapping)
• SQL vs NoSQL
• NoSQL properties (schemaless, aggregate orientation, transactions, …)
• Types of NoSQL databases: KV, Document, Column-family, Graph

Distribution Models

• Consistency problem
• Sharding
• Replication
• Consistency models: eventual consistency, monotonic reads, read your writes, strong consistency. Consistency guarantee
• MongoDB and Cassandra parameters for consistency guarantee

CAP theorem

• CAP theorem. BASE.
• CAP theorem with SQL and NoSQL DBs
• Polyglot Persistence

Module 3 MapReduce

• Data locality. Phases
• Standard algorithms: Word count, Inverted index, Top N
• Map/Reduce/Combine functions requirements
• MapReduce alternatives
• RDBMS vs NoSQL vs MapReduce

Module 4 Distributed systems

• Consensus problem. Split-brain problem. Byzantine Generals problem.
• Distributed systems: Communication, Failure Modes, Leader, Consensus, Quorums, Time, Order
• Vector/Lamport Clock

Consensus protocols

• Replicated state machine
• Raft protocol
• Paxos protocol

Preliminary practical tasks

• Map/Reduce implementation*
• 2PC protocol
• MongoDB basics
• Neo4J basics
• Cassandra data model basics
• MongoDB replication
• Cassandra replication
• MongoDB Map/Reduce
• Raft protocol*

Prerequisites

None