Collect all entity sizes in a Postgres DB in high resolution

sys_get_sizes

SELECT pg_statio_user_tables.schemaname,
    pg_statio_user_tables.relname,
    pg_size_pretty(pg_total_relation_size(pg_statio_user_tables.relid::regclass)) AS total_size,
    pg_size_pretty(pg_relation_size(pg_statio_user_tables.relid::regclass, 'main'::text)) AS relation_size_main,
    pg_size_pretty(pg_relation_size(pg_statio_user_tables.relid::regclass, 'fsm'::text)) AS relation_size_fsm,
    pg_size_pretty(pg_relation_size(pg_statio_user_tables.relid::regclass, 'vm'::text)) AS relation_size_vm,
    pg_size_pretty(pg_relation_size(pg_statio_user_tables.relid::regclass, 'init'::text)) AS relation_size_init,
    pg_size_pretty(pg_table_size(pg_statio_user_tables.relid::regclass)) AS table_size,
    pg_size_pretty(pg_total_relation_size(pg_statio_user_tables.relid::regclass) - pg_relation_size(pg_statio_user_tables.relid::regclass)) AS external_size
   FROM pg_statio_user_tables
  ORDER BY (pg_total_relation_size(pg_statio_user_tables.relid::regclass)) DESC;