Find Table Size
SELECT pg_database.datname,pg_size_pretty(pg_database_size(pg_database.datname)) AS size FROM pg_database where datname='database_name';
Batch Update Table Owners
Using only SQL to change owners of all tables in a database.
select 'alter table '|| tablename ||' owner to ;' from pg_tables where schemaname = 'public';
Or, using the slightly more dangerous:
UPDATE pg_class SET
relowner = (SELECT oid FROM pg_roles WHERE rolname = '$USER')
WHERE relname IN
(SELECT relname FROM pg_class, pg_namespace
WHERE pg_namespace.oid = pg_class.relnamespace AND pg_namespace.nspname = 'public');