On Fri, 2019-10-04 at 00:34 +1000, Jason Wang wrote: > I read this > https://www.2ndquadrant.com/en/blog/evolution-fault-tolerance-postgresql-synchronous-commit/ > > But don't see why your primary would have more records than the > standby? > > If killall was issued before commit returned, that means the > transaction wasn't completed so yes you would lose records after last > commit but that's expected; if commit was returned both primary and > standby should have the transaction. > > Are you sure in your case you end up with primary and standby with > different records from a single transaction?
PostgreSQL synchronous streaming replicatoin doesn't use anything like two-phase commit. 1. It commits the transaction locally first, which generates WAL. 2. The WAL gets replicated. 3. As soon as the standby reports success, COMMIT returns. If there is a failure after the first step completed, the transaction will be committed locally, but not on the standby. Yours, Laurenz Albe -- Cybertec | https://www.cybertec-postgresql.com
