Dados PostgreSQL e tamanho do índice por tabela

SELECT N.nspname || '.' || C.relname AS "relation",
    CASE WHEN reltype = 0
        THEN pg_size_pretty(pg_total_relation_size(C.oid)) || ' (index)'
        ELSE pg_size_pretty(pg_total_relation_size(C.oid)) || ' (' ||  pg_size_pretty(pg_relation_size(C.oid)) || ' data)'
    END AS "size (data)",
    COALESCE(T.tablespace, I.tablespace, '') AS "tablespace",
    COALESCE(TS.spclocation, XS.spclocation, '') AS "location"
FROM pg_class C
LEFT JOIN pg_namespace N ON  (N.oid = C.relnamespace)
LEFT JOIN pg_tables T ON (T.tablename = C.relname)
LEFT JOIN pg_indexes I ON (I.indexname = C.relname)
LEFT JOIN pg_tablespace TS ON TS.spcname = T.tablespace
LEFT JOIN pg_tablespace XS ON XS.spcname = I.tablespace
WHERE nspname NOT IN ('pg_catalog','pg_toast','information_schema')
ORDER BY pg_total_relation_size(C.oid) DESC;