Find the database tables that are using the most space on disk

gistfile1.txt

SELECT relname AS "tablename", reltuples AS "rows", relpages * 8 / 1024 AS "MB" FROM pg_class 
WHERE relname like 'alf%' 
OR relname like 'act%' 
OR relname like 'avm%' 
OR relname like 'jbpm%' 
ORDER BY relpages DESC;

C:\Alfresco514\postgresql\bin>pg_resetxlog.exe C:\Alfresco514\alf_data\postgresql
Transaction log reset

select current_query from pg_stat_activity where
current_query <> '' and current_query not like
'%pg_stat_activty%';

-- Find the total space occupied by documents on disk
SELECT count(*),round(SUM(u.content_size)/1024/1024, 3) AS "Size (MB)", to_char(n.audit_created:: date,'yyyy') as yyyy_
FROM alf_node AS n,
alf_node_properties AS p,
alf_node_properties AS p1,
alf_namespace AS ns,
alf_qname AS q,
alf_content_data AS d,
alf_content_url AS u
WHERE n.id=p.node_id
AND ns.id=q.ns_id
AND p.qname_id=q.id
AND p.long_value=d.id
AND d.content_url_id=u.id
AND p1.node_id=n.id
AND p1.qname_id IN (SELECT id FROM alf_qname WHERE local_name='name')
group by yyyy_
ORDER BY yyyy_ DESC;