What is the difference in record confirmation timing between synchronous and asynchronous replication?

In synchronous replication, a write is considered confirmed to the client only after the data is successfully written to the primary and all replicas. This guarantees that data will not be lost in case of a failure, but increases response latency.

In asynchronous replication, the write is confirmed to the client immediately after it is written to the primary node, and the data on replicas is transmitted with a delay. This reduces response time, but there is a risk of data loss if the primary node fails before replication.

Example:

• Synchronous: client sends request → primary and replicas confirm the write → client receives response.
• Asynchronous: client sends request → primary confirms the write → client receives response → replicas are updated later.