strange bug in plperl

Can anyone suggest why I might be seeing this effect (each notice comes
out once per row plus once per function call)

thanks

andrew

andrew=# create function tstset() returns setof tst language plperl as $$
andrew$# elog(NOTICE,"tstset called");
andrew$# return [{i=>1,v=>"one"},{i=>2,v=>"two"}];
andrew$# $$;
CREATE FUNCTION
andrew=# select * from tstset();
NOTICE: tstset called
NOTICE: tstset called
NOTICE: tstset called
i | v
---+-----
1 | one
2 | two
(2 rows)