Terminology for PostgreSQL®

• Primary node: The PostgreSQL® primary node is the main server node that processes SQL queries, makes the necessary changes to the database files on the disk, and returns the results to the client application.

• Standby node: PostgreSQL standby nodes (also called replicas) replicate the changes from the primary node and try to maintain an up-to-date copy of the same database files that exists on the primary node.

• Write-Ahead Log (WAL): The WAL is a log file storing all the database transactions in a sequential manner.

• pglookout: pglookout is a PostgreSQL replication monitoring and failover daemon.

• PGHoard: PGHoard is a PostgreSQL backup daemon and restore tooling that stores backup data in cloud object stores