Allow scaling Materialize along with Chain for created "MV on MV".

[BugenZhao]

This is the only case of no-shuffle exchange now. To support scaling them simultaneously, we can specify that only upstream Materialize is allowed to be the target of rescheduling.

• After feat: enforce chain parallelism and fill proper upstream with same vnode range #4740, we're ensured that the parallel units of Chain must be the same as the upstream Materialize, connected with no-shuffle exchange.
• If we're asked to scale the Materialize, we need to resolve the downstream Chain and clone the plan for it.
• The resolving is recursive:
  • It's possible the downstream MV is simple enough, so the Chain fragment itself also includes a Materialize. Then we need to check the down-downstream.

  dev=> create table t (v int);
  CREATE_TABLE
  dev=> create materialized view mv1 as select * from t order by v limit 10;
  CREATE_MATERIALIZED_VIEW
  dev=> create materialized view mv2 as select * from mv1;
  CREATE_MATERIALIZED_VIEW
  dev=> create materialized view mv3 as select * from mv2;
  CREATE_MATERIALIZED_VIEW
  

  • Is it possible the fragment of Chain has another upstream? Not possible after fix: use UpstreamHashShard distribution for table scan #4534 for HashJoin, but possible for the DynamicFilter (or even NestedLoopJoin) if we implement RFC: add logical property Cardinality on PlanNode #2279. Luckily, the inner side of DynamicFilter must be a singleton, so there might be no need to worry about this.
• Disallow directly scale the fragment containing Chain. So we must at the top when resolving recursively.
• If the state of any of the table fragments is Creating in the recursive resolving results, we should refuse this request.
  

  risingwave/proto/meta.proto

  Lines 33 to 42 in 0717524

  	// Fragments of a Materialized View
  	message TableFragments {
  	// The state of the fragments of this table
  	enum State {
  	UNSPECIFIED = 0;
  	// The materialized view is creating
  	CREATING = 1;
  	// The materialized view has been created
  	CREATED = 2;
  	}