Motivation

Richard Feynman - “What I cannot create, I do not understand”

As someone without a background in databases, I’ve always been curious about the inner workings of transactions in OLTP databases such as PostgreSQL and CockroachDB. To unveil the mystery, I studied CockroachDB's transactional layer extensively and built a toy, transactional key-value database by reimplementing many techniques and algorithms used by CockroachDB's transactional layer, such as its MVCC system, read refresh, deadlock detection algorithm, and others.

Here is a quick summary of the toy database I built:

• key-value database
• thread-safe
• uses RocksDB as the storage engine
• written in Rust (my first time learning Rust!)
• support transactions
• SSI (serializable Snapshot Isolation)
• uses MVCC (multi-version concurrency control)
• uses pessimistic write locks and optimistic reads (reads are lock-free)

In this blog series, I will cover the theory behind and the implementation of my toy database. The source code is available on GitHub here.