Process Architecture PostgreSQL uses a multi-process architecture rather than threads. The postmaster is the root process: it listens for incoming

Single-Threaded Event Loop Redis processes all client commands on a single main thread sequentially. This design eliminates the need for

Why CPU Cache Optimization Matters Modern CPUs execute instructions in nanoseconds, but DRAM access takes ~80ns — roughly 200 CPU

What Is a Virtual Memory System? Virtual memory is a foundational OS abstraction that gives each process the illusion of

Relational databases have been the default choice for decades, and for good reason — SQL is powerful, ACID transactions are

Concurrency is one of the hardest problems in systems design. Bugs are non-deterministic, hard to reproduce, and can corrupt data

Compression is one of the highest-leverage primitives in systems design. It reduces storage cost, cuts network bandwidth, and often improves

A data warehouse is a system optimized for analytical queries across large volumes of historical data. Unlike transactional databases, warehouses

An audit log is an immutable, chronological record of every significant action taken in a system — who did what

DNS (Domain Name System) is the internet’s distributed directory service — it translates human-readable hostnames like www.example.com into IP addresses

Idempotency is the property that an operation produces the same result whether it is applied once or multiple times. In