Topic
Multiversion and optimistic concurrency control, multi-process writes and transaction conflict behaviour.
Both Astra + Luna runs of a SQLite job queue cleared their acceptance tests yet computed leases from a clock read taken before the write lock. An audit exposed it by holding one writer behind a barrier and advancing an injected clock during the other's wait.
Reality
ParkEase puts slot exclusivity in PostgreSQL 18, where no write path can skip it. The mechanism is a GiST exclusion constraint, and the cost lands on whichever booking request loses the race at insert time.
Reality
A dev.to teardown makes the case for event-triggered Node workers with a slow poll behind them, and the idle-cost numbers it publishes come to about 138,000 empty queries a day across eight instances.
Reality
A dev.to teardown of payment idempotency argues the header is a token and the guarantee is a document. The parts nobody writes down fail during outages, when nobody is looking.
Reality
The creators of the embedded analytics engine are adding the client-server layer their original design deliberately left out. Treat v2.0 as a provisioning decision, not an upgrade.
Reality