"John R Pierce" <pierce@hogranch.com> writes:
>> You've got some background client holding a transaction open. Or else
>> the test program isn't really committing when you think it is.
> there are no background programs. I've done all the usual checking of `ps'
> outputs looking for such.
> in the test case I mailed to this list, I had created a standalone database
> with one table, and run the test program directly against it.
That sounds suspiciously like you think that only background clients
connected to the same database count. Actually, any other client
connected to the same *postmaster* can look like an open transaction
to VACUUM ...
regards, tom lane