PG Bug reporting form <noreply(at)postgresql(dot)org> writes:
> create extension postgres_fdw;
> ERROR: could not load library "/usr/pgsql-10/lib/postgres_fdw.so":
> /usr/pgsql-10/lib/postgres_fdw.so: undefined symbol: change_plan_targetlist
This looks like a version mismatch problem --- your postgres_fdw is newer
than your server (possibly just a minor release newer, but still newer).
It's unfortunate that the error message isn't more on-point, but we don't
have enough control over the dynamic linker to make it so.
regards, tom lane