Notes and articles about how databases store, query, and coordinate data.
What Does Freezing a Row Mean in PostgreSQL?
A short explanation of frozen rows, transaction ID wraparound, and why vacuum needs to freeze old tuple metadata.
Topic
Databases
Storage engines, file formats, concurrency control, MVCC, and query execution.
How Does Parquet Store JSON Objects?
How Parquet represents nested JSON data using flattened columns, repetition levels, and definition levels.
PostgreSQL Vacuum
How PostgreSQL vacuum works, and what I got wrong along the way
PAX, Row Groups, and Parquet
How PAX-style layouts and Parquet organize data for analytics, and what I got wrong along the way
Two-Phase Locking (2PL)
How two-phase locking controls concurrent transactions, and what I got wrong along the way
Database Concurrency Models
How databases handle multiple clients at once, and what I got wrong along the way
Linearizability
What linearizability means in distributed systems, and what I got wrong along the way
SQLite Query Execution
How SQLite processes a query from SQL text to results, and what I got wrong along the way
Log-Structured Merge Trees
How LSM trees trade read performance for fast writes, and what I got wrong along the way