+=item B<backends>
+
+This query collects the number of backends, i.E<nbsp>e. the number of
+connected clients.
+
+=item B<transactions>
+
+This query collects the numbers of committed and rolled-back transactions of
+the user tables.
+
+=item B<queries>
+
+This query collects the numbers of various table modifications (i.E<nbsp>e.
+insertions, updates, deletions) of the user tables.
+
+=item B<query_plans>
+
+This query collects the numbers of various table scans and returned tuples of
+the user tables.
+
+=item B<table_states>