I have a workaround for the mysterious inability to delete records
from one particular table not notably different from many others.
This does not explain the problem, but at least enables me to move
on... Whether all of the following steps are necessary I can't say.
Instead of loading the 9.3 DB with a dump from 8.4, I did a two
step dump-reload through an intermediate system with 9.1, first
clearing the 9.3 DB of any residues from the previous load. This
included eliminating all references to users, which in turn
required using a REASSIGN for template1 to postgres.
Retained the "superuser" status for deleting the rows. This did not
work previously (I can recreate the problem by altering the role to
mere CREATEROLE CREATEDB) and with the user in question being the
owner of the table.
This makes me a bit nervous, as I don't understand why, but at least
it seems to work.
-Frank