“With the PostgreSQL heap engine, the update of a single indexed field disables HOT, so all indexes get updated.”
Postgres VACUUM is a leftover from Berkeley’s infinite time-travel experiment, and its MVCC design still bloats tables decades later. OrioleDB swaps in row-level and block-level undo logs, in-place updates and automatic page merging. The benchmark is a sparse upsert across five indexes, the exact workload where heap tables bloat worst. The vendor picked the test its engine was built to win.