PostgreSQL table sizes

SELECT
 schema_name,
 relname,
 pg_size_pretty(table_size) AS size,
 table_size

FROM (
      SELECT
        pg_catalog.pg_namespace.nspname           AS schema_name,
        relname,
        pg_relation_size(pg_catalog.pg_class.oid) AS table_size

      FROM pg_catalog.pg_class
        JOIN pg_catalog.pg_namespace ON relnamespace = pg_catalog.pg_namespace.oid
    ) t
WHERE schema_name NOT LIKE 'pg_%'
ORDER BY table_size DESC;

Related

• PostgreSQL: \dt