Re:

Wade Klaver <archeron@wavefire.com> writes:
> dropsites=# vacuum full  analyze;
> WARNING:  Rel pg_type: TID 12/46: InsertTransactionInProgress 27217603 - can't
> shrink relation
> WARNING:  Rel pg_type: TID 12/47: InsertTransactionInProgress 27217603 - can't
> shrink relation
> WARNING:  Rel pg_attribute: TID 152/1: InsertTransactionInProgress 27217603 -
> can't shrink relation
> WARNING:  Rel pg_attribute: TID 152/2: InsertTransactionInProgress 27217603 -
> can't shrink relation
> ...
> ...
> And so on.  The source code says "this should never happen".

7.4 has downgraded those messages to NOTICEs, and says

                    /*
                     * This should not happen, since we hold exclusive
                     * lock on the relation; shouldn't we raise an error?
                     * (Actually, it can happen in system catalogs, since
                     * we tend to release write lock before commit there.)
                     */

If you saw it on anything besides a system catalog, then I'm interested,
but otherwise not to worry.

BTW, you really should update to 7.3.4.

            regards, tom lane