In PostgreSQL, logical replication is the process of copying and maintaining database objects in multiple locations, which can happen synchronously or asynchronously at various levels. The Write-Ahead Log (WAL) plays a crucial role in ensuring data consistency and recovery from crashes. Logical replication allows for flexible replication of specific tables, rows, or columns, making it suitable for syncing transactional data to data lakes or warehouses. Airbyte provides connectors for PostgreSQL-to-external-data-store logical replication, enabling the creation of an EL pipeline with community-built and maintained connectors. Neon's support for logical replication and pairing with Airbyte Cloud offers a scalable solution for serverless PostgreSQL deployments in the cloud. By configuring WAL settings, such as wal_compression, max_wal_size, and min_wal_size, users can optimize disk space usage and improve replication performance.