MTAR T3D Sessions: PostgreSQL Is Still Paying for Old MVCC Decisions

More than a refresh: Conversations with the most interesting people you've never met · Jun 9, 2026 · 12m

In this Postgres Pet Peeves episode, JD talks with Jonah Harris about one of PostgreSQL’s oldest and most debated architectural choices: MVCC and the storage behavior that still shapes how PostgreSQL handles updates, concurrency, and vacuum today.

Jonah explains how PostgreSQL originally supported time-travel queries, allowing users to inspect historical versions of data directly, and why PostgreSQL still stores and manages data the way it does even after those original features disappeared decades ago.

From there, the conversation digs into the real consequences of PostgreSQL’s MVCC model…