Get all schema sizes

SELECT schema_name,
pg_size_pretty(SUM(table_size)::BIGINT) AS "disk space",
(SUM(table_size) / pg_database_size(current_database())) * 100
AS "percent"
FROM (
SELECT pg_catalog.pg_namespace.nspname AS schema_name,
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
GROUP BY schema_name
ORDER BY schema_name;