Cross engine join hanging on even 1gb tpch joins, the first one finishes sometimes

select count ( * ) from lineitem a, myisamdb.orders b where a.l_orderkey = b.o_orderkey and b.o_custkey = 1;

select count ( * ) from lineitem a, myisamdb.orders b where a.l_orderkey = b.o_orderkey and b.o_orderkey < 10 and substr(b.o_orderpriority,1,2) = '1-';