请问下，对于PhysicalHashJoin得hash属性是怎么计算的。
是否也是类似于orca呢？
// given an optimization context, HJN creates three optimization requests
// to enforce distribution of its children:
// Req(1 to N) (redistribute, redistribute), where we request the first hash join child
// to be distributed on single hash join keys separately, as well as the set
// of all hash join keys,
// the second hash join child is always required to match the distribution returned
// by first child
// Req(N + 1) (hashed, broadcast)
// Req(N + 2) (non-singleton, broadcast)
// Req(N + 3) (singleton, singleton)