Documentation comparison
Compare the promises.
Pick up to four systems. Read the qualification before treating any capability as equivalent. These are documentation/source claims, not benchmark results.
Compare mechanisms, not checkmarks.
Uniqueness at enqueue, protection of a running attempt and provider idempotency solve different problems. “Qualified” retains limits; “Not verified” is an evidence gap.
The extension row describes the selected PostgreSQL path. Optional extensions, other databases and proprietary additions are noted in the cells. Sources checked 2026-10-23.