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 -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance