I wrote:
> Hmm, we could probably fix that if we made the cluster operation swap
> the physical storage of the two toast tables, rather than swapping the
> tables altogether. I agree it's not critical but it could be confusing.
On second thought, I think it *could* lead to a visible failure.
Suppose the OID counter wraps around and the OID that had been used for
the temporary CLUSTER table gets assigned to a new table. If that table
needs a toast table, it'll try to create one using the name that is
already in use. We have defenses against picking an OID that's in use,
but none for toast table names. So I think it's indeed worth fixing.
regards, tom lane