liste des schémas avec tailles (relatives et absolues) dans une base de données PostgreSQL

Essayez ceci :

SELECT schema_name, 
       sum(table_size),
       (sum(table_size) / database_size) * 100
FROM (
  SELECT pg_catalog.pg_namespace.nspname as schema_name,
         pg_relation_size(pg_catalog.pg_class.oid) as table_size,
         sum(pg_relation_size(pg_catalog.pg_class.oid)) over () as database_size
  FROM   pg_catalog.pg_class
     JOIN pg_catalog.pg_namespace ON relnamespace = pg_catalog.pg_namespace.oid
) t
GROUP BY schema_name, database_size

Modifier :je viens de remarquer que la solution de contournement consistant à additionner toutes les tables pour obtenir la taille de la base de données n'est pas nécessaire :

SELECT schema_name, 
       pg_size_pretty(sum(table_size)::bigint),
       (sum(table_size) / pg_database_size(current_database())) * 100
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