Internals

PostgreSQL Stores a Row

Oct 20, 2026 25 min read Jay Hubbert

Every database gives you a row and every database lies a little about what that row is. MySQL gives you a record copied into a row buffer. SQLite gives you a record in a b-tree …

Postgres Storage Internals

PostgreSQL's time and timetz Implementation in C

Oct 12, 2026 7 min read Jay Hubbert

A PostgreSQL time is a 64-bit integer counting microseconds since midnight. A timetz is the same integer plus a 4-byte timezone offset. So far so simple. The interesting part is …

Postgres Internals Time Timetz

PostgreSQL Speeds Up Hash Joins

Oct 11, 2026 31 min read Jay Hubbert

A hash join is the simplest join algorithm in the database: build a hash table from the inner relation, then probe it once per outer row. There is no sort, no merge, no nested loop …

Postgres Performance Executor Internals

PostgreSQL's numeric Implementation in C

Oct 8, 2026 10 min read Jay Hubbert

numeric is PostgreSQL’s exact decimal type: arbitrary precision, no rounding surprises, no binary-vs-decimal conversion error. It is also the type where the storage format and the …

Postgres Internals Numeric Decimal

PostgreSQL Waits for Locks

Oct 6, 2026 49 min read Jay Hubbert

Every lock in PostgreSQL is a bet. When a backend wants a resource that somebody else has, it has to choose: burn CPU waiting, or go to sleep and let the kernel schedule somebody …

Postgres Performance Concurrency Internals