dt_pq_getvalue
v = dt_pq_getvalue(p, lc);
uint64_t lv = dt_pq_getvalue(p, lc);
uint64_t rv = dt_pq_getvalue(p, rc);
if (v >= dt_pq_getvalue(p, i))
while (i > 1 && dt_pq_getvalue(p, i) < dt_pq_getvalue(p, i / 2)) {