Followup: vacuum'ing toast

Thanks folks for the quick replies.

1. There is one transaction, connected from the JVM, that is showing
"IDLE in transaction" .... this appears to be a leftover from
Hibernate looking at the schema metadata. It's Apache Jackrabbit, not
our own code:

hyper9test_1_6=# select c.relname, l.* from pg_class c, pg_locks l
where c.relfilenode=l.relation and l.pid in (select procpid from
pg_stat_activity where current_query='<IDLE> in transaction');
          relname           | locktype | database | relation | page |
tuple | virtualxid | transactionid | classid | objid | objsubid |
virtualtransaction | pid  |      mode       | granted

----------------------------+----------+----------+----------+------+-------+------------+---------------+---------+-------+----------+--------------------+------+-----------------+---------
 pg_class_oid_index         | relation |   280066 |     2662 |      |
     |            |               |         |       |          | 3/18
             | 8069 | AccessShareLock | t
 pg_class_relname_nsp_index | relation |   280066 |     2663 |      |
     |            |               |         |       |          | 3/18
             | 8069 | AccessShareLock | t
 pg_description_o_c_o_index | relation |   280066 |     2675 |      |
     |            |               |         |       |          | 3/18
             | 8069 | AccessShareLock | t
 pg_namespace_nspname_index | relation |   280066 |     2684 |      |
     |            |               |         |       |          | 3/18
             | 8069 | AccessShareLock | t
 pg_namespace_oid_index     | relation |   280066 |     2685 |      |
     |            |               |         |       |          | 3/18
             | 8069 | AccessShareLock | t
 pg_class                   | relation |   280066 |     1259 |      |
     |            |               |         |       |          | 3/18
             | 8069 | AccessShareLock | t
 pg_description             | relation |   280066 |     2609 |      |
     |            |               |         |       |          | 3/18
             | 8069 | AccessShareLock | t
 pg_namespace               | relation |   280066 |     2615 |      |
     |            |               |         |       |          | 3/18
             | 8069 | AccessShareLock | t
 version_node               | relation |   280066 |   493309 |      |
     |            |               |         |       |          | 3/18
             | 8069 | AccessShareLock | t
 version_node_idx           | relation |   280066 |   493315 |      |
     |            |               |         |       |          | 3/18
             | 8069 | AccessShareLock | t
(10 rows)

Since the Jackrabbit tables are in the same namespace / user / schema
as ours, am I right in thinking that this is effectively blocking the
entire auto-vaccum system from doing anything at all?

Cheers
Dave