If you use 1-safe replication with HotStandby (HSB), the commit statement is acknowledged immediately after the commit processing is completed on the primary server. The committed transaction is transmitted to the secondary server asynchronously, after the control has been returned to the application.
Description
Illustration
Application commits transaction.
Primary server acknowledges committed transaction.
Primary server sends committed transaction to secondary server.
Secondary server acknowledges committed transaction.
The delay in transmitting the transaction can range from a few milliseconds to a few hundred milliseconds. 1-safe replication offers significant performance gains because the latencies are reduced dramatically on the primary server. The downside of 1-safe replication is that, in the case of a failure, a few transactions can be lost.
