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 is a PostgreSQL replication monitoring and failover daemon.
PGHoard is a PostgreSQL backup daemon and restore tooling that stores backup data in cloud object stores