William Blunn <bill+postgresql(at)blunn(dot)org> writes:
> Will the query engine retrieve the entire row (including 10 megabytes of
> out-of-line TOASTed data) for every row, and then pick out column
> "name", and take an age to do so,
No. That's pretty much the whole point of the TOAST mechanism;
out-of-line values are not fetched unless actually needed. See
http://developer.postgresql.org/pgdocs/postgres/storage-toast.html
regards, tom lane