"ERROR: invalid transaction termination" when trying to execute a procedure with nested transaction control

Question

According to the documentation (https://www.postgresql.org/docs/current/app-psql.html), even with AUTOCOMMIT set to off, PSQL issues an implicit BEGIN just before any command that is not already in a transaction block and is not itself a BEGIN or other transaction-control command, nor a command that cannot be executed inside a transaction block such as VACUUM. (Unfortunately CALL is not treated in the same way as VACCUM). And, according to Shaun Thomas (https://blog.2ndquadrant.com/pg-phriday-stored-procedures-postgres-11/), the invalid transaction termination error happens because it is not possible to close the current transaction (in this case the one initiated by PSQL) from within the procedure. I have tried with all the PSQL settings related to transaction control, but the invalid transaction termination error occurs with all of them; even if the commands file processed by PSQL contains only the CALL statement.

This is the procedure I'm calling:

create or replace procedure producto$cargar_imagenes(_super$ bigint, _archivo$ character varying) as $$
declare
    _msg character varying;
    _log rastro_proceso%ROWTYPE;
begin
    perform rastro_proceso_temporal$insert(_super$);
    perform producto$cargar_imagenes$biz(_super$, _archivo$);
    if (_super$ is not null and _super$ > 0) then
        perform producto$cargar_imagenes$log(_super$, _archivo$);
    else
        perform tarea_usuario$private$update(6519204281880642486, null);
    end if;
    commit;
end;
$$ language plpgsql set search_path = public;

It fails at the commit statement; it works if I comment it out.

Answer 1

Remove the SET clause. Per the documentation:

If a SET clause is attached to a procedure, then that procedure cannot execute transaction control statements (for example, COMMIT and ROLLBACK, depending on the language).