Consulta lenta em tabela com campo bytea

SELECT relname, pg_size_pretty(relpages*8192) as "tamanho" 
  from pg_class
 where relname = 'comimgcl'

SELECT n.nspname AS schemaname, 
       c.relname AS tablename, 
       C.reltuples AS Registros, 
       pg_size_pretty(pg_relation_size(n.nspname ||'.'||c.relname)) as Tamanho
FROM pg_class c
LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
LEFT JOIN pg_tablespace t ON t.oid = c.reltablespace
WHERE c.relkind = 'r'
AND n.nspname = 'public'
AND c.relname = 'comimgcl'

select relname,pg_relation_size(oid),pg_table_size(oid) 
  from pg_class
 where relname = 'comimgcl';