Was it streaming or batch replication?

Streaming replication transmits data changes in real-time by sending WAL (Write-Ahead Log) records immediately after they are created. This ensures minimal latency between the master and replica and is suitable for systems where data freshness is important.

Batch (or logical) replication collects changes into batches and sends them periodically. This can be useful for reducing network load or when instant synchronization is not required.

For example, PostgreSQL supports streaming replication, where the slave connects to the master and receives WAL records continuously, as well as logical replication, which operates at the level of table changes and can filter data.