The last paragraph mentions the dblink module, but surely postgres_fdw
deserves a mention here too - especially with its increasing ability to push
more of the query onto the foreign servers.
Also, I think it would be worth mentioning elsewhere in the documentation
(e.g. https://www.postgresql.org/docs/10/static/indexes-types.html) the
impact that maintenance_work_mem has on the creation time for different
index types - currently I can't find this anywhere else except on this FTS