Review Postgres docs in /doc/administration

Problem to solve

The documentation in https://docs.gitlab.com/ee/administration/postgresql/ is probably old and crusty. Is it still valid? Should we keep it / update it / clean it up?

This work is NOT urgent, and has no specific milestone deadline.

(issue description inherited from #381814 (closed))

Further details

• https://docs.gitlab.com/ee/administration/postgresql/
  • https://docs.gitlab.com/ee/administration/postgresql/replication_and_failover.html
  • https://docs.gitlab.com/ee/administration/postgresql/standalone.html
  • https://docs.gitlab.com/ee/administration/postgresql/pgbouncer.html
  • https://docs.gitlab.com/ee/administration/postgresql/database_load_balancing.html
  • https://docs.gitlab.com/ee/administration/postgresql/external.html
  • https://docs.gitlab.com/ee/administration/postgresql/moving.html

Proposal

While I'd would love to get these pages reviewed, I know the groupdatabase engineers are already wearing a lot of hats. I can polish and clean up existing text, but here's what I'd ask for help with:

• Is the info on a page out of date?
• Is the info on this page wrong?
• Should this page / this subheading continue to exist in our docs?

I rely on my engineers to answer those questions. Don't worry about style and formatting (but obviously tell me if something looks really bad to your eyes!) - that part is my job.

Who can address the issue

Engineers in groupdatabase and groupdistribution.

Other links/references

• Related to Update doc/administration/troubleshooting/postg... (!102873 - merged) where a revision from Support came in.
• Related to Follow-up from "Update doc/administration/troub... (#381605 - closed), the follow-up issue I made to clean up the rest of that page. It made me realize this entire directory might be dirty / old.