Hubert Zhang <hzhang(at)pivotal(dot)io> writes:
> I wonder if there is a way to let a child process of postmaster to access
> all the databases one by one?
No. For starters, you'd need some way to flush all database-specific
information from relcache, catcache, and a boatload of other places;
but that logic does not exist.
regards, tom lane