Note

CS Degree Day 86

CS Degree in 100 Days

03 Sep'25

What I did today?

Lecture 9: Recovery - write-ahead logging, ARIES protocol
Lecture 10: Distributed databases - CAP theorem, consistency models
Problem set: Trace through ARIES recovery

CAP Theorem says that out of Consistency, Availability and Partition tolerance you can only choose two. In a distributed system, partitions are not optional. They happen. So the real choice is between consistency and availability. This is why DynamoDB is eventually consistent and why Postgres with synchronous replication can lag.

Back to notes Return home