After fixing the problem with utility statements, this whole block:
do $$
declare
n integer:= 1;
begin
loop
PERFORM a,b,c,d FROM t1, t2, t3, t4
WHERE t1.a = t2.b AND t3.c = t4.d ORDER BY a;
exit when n = 1000;
n := n + 1;
end loop;
end $$;
Is only processed once, as those are nested statements, in order to
match the 1000 statements the GUC pg_stat_monitor.track must be set to
'all' and then back to the default of 'top' when done testing it.
a716273f19