The article explores PostgreSQL's TOAST (The Oversized-Attribute Storage Technique) system, explaining how it handles large column values by storing them in separate shadow tables with chunked pointers. The author shares a real-world anecdote about a poorly performing event_log table caused by unconstrained TEXT/XML columns, illustrating TOAST's hidden performance costs.
Background
TOAST is PostgreSQL's internal mechanism for handling column values that exceed the 8KB page size limit, transparently compressing and offloading data to secondary storage tables.
- Source
- Lobsters
- Published
- Nov 5, 2026 at 02:00 AM
- Score
- 6.0 / 10