0086 — The knob is set via ALTER DATABASE, and reset to on after the sweep
Edit this pagePosted: 2026-09-08
Context. The benchmark drives Postgres through a pgx connection pool. A session-level SET synchronous_commit=off applies only to the session that issued it and would never reach the pool’s other connections, silently benchmarking a mix of settings.
Decision. Set the knob with ALTER DATABASE example_db SET synchronous_commit=off, which every pool connection inherits at connect time; after the sweep, RESET it back to the default on.
Consequences. Sweep results reflect a uniform setting across all connections. The dev database is not left silently non-durable — adopting off later is a deliberate re-run of the same ALTER, not a leftover. Rejected: session-level SET — it does not propagate to pooled connections.