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.
Databases · systems · performance
low-level-luke
Technical notes, experiments, and active-recall braindumps about the lower layers of software.
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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