QPSQL unable to COPY large files

I am trying to make a fuction for create a large table from file using COPY.
My function create the *.csv file properly.
After, my function generate the query, who calls to a postgres function that uses COPY command.

This is the postgres function:

Code:

---

CREATE OR REPLACE FUNCTION importar_copy(
    _nombretabla character varying,
    _ruta character varying)
  RETURNS boolean AS
$BODY$
DECLARE
texto text;
BEGIN
	texto = FORMAT ('COPY %I FROM %s DELIMITER %s NULL AS ''NULL''', _nombretabla, quote_literal(_ruta), quote_literal(chr(9)));
	execute (texto);
	raise notice '%',texto;
	return true;
END;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;

---

As well as I have said, the function in Qt generate the query properly. And the file is also properly generate. If I copy the query generate in Qt and paste in pgAdmin, the query works, but if I try to exec from my Qt application, is like if it can manage a large file and stop to read in any place of it.

Maybe someone knows what could happens?
Thank you very much!