> MongoDB has built-in auto-failover with replica sets. It is possible to set this up for PGSQL with third-party tools but it's hard to get right.

PostgreSQL documentation makes it quite clear how to set up HA, I don't think you need any third-party tools other than general OS-level support for failover.

https://www.postgresql.org/docs/current/high-availability.ht...

I don't think PostgreSQL supports out of the box auto-failover as MongoDB does. It either needs custom scripting or tools like repmgr.

From the official docs:

>> PostgreSQL does not provide the system software required to identify a failure on the primary and notify the standby database server. Many such tools exist and are well integrated with the operating system facilities required for successful failover, such as IP address migration. [1]

[1]https://www.postgresql.org/docs/current/warm-standby-failove...

Or Patroni (https://github.com/zalando/patroni), a better option. But it is complex to setup, requires other external tools too (DNS, virtual IPs, Envoy proxy, etc) and none of that is included in Postgres.

Postgres HA is far from easy. I gave a talk 2 years ago about this (video and slides: https://aht.es/#talks-modern_postgresql_high_availability). This is an operational disadvantage.