Query below return table which uses 50% of summary space used by all database tables.
select schemaname as table_schema, relname as table_name, pg_size_pretty(pg_relation_size(relid)) from pg_catalog.pg_statio_user_tables where pg_relation_size(relid) > 0.5 * ( select sum((pg_relation_size(relid))) from pg_catalog.pg_statio_user_tables);
- table_schema - name of schema
- table_name - name of table
- data_size - space used by table
- Query should return one row