Postgresql high availability

Documentation

postgres: high availability	https://www.postgresql.org/docs/current/high-availability.html
postgres: logical replication	https://www.postgresql.org/docs/10/logical-replication.html

Discussion

HA Postgres Options Overview -- 2019 postgres-(8.0-9.2)	https://www.youtube.com/watch?v=fsMvr96gTjY
Evolution of HA Postgres -- 2018 postgres-(8.0-10.0)	https://www.youtube.com/watch?v=ntVjVNnilX0

Overview

There are a handful of different ways to do this, but most seem to be centered around the following concepts;

• Alternate modes are configured in postgres.conf
• In some modes, transactions are recorded on disk as WAL files (wal==Write-Ahead-Log)
• You or Postgres-mode copies these WAL files to all standby servers.
• Standby servers ingest WAL files

Standby servers can be in separate datacenters, but in almost every case, only the primary database is ever written to. Strategies involving Hot Standbies mean the servers can be read from.

Strategies

Postgres-8.0	Postgres HA: Warm Standby
Postgres-8.2+	Postgres HA: Hot Standby
Postgres-10.0+	Postgres HA: Logical Replication (hot standby)