Rework on serialization and deserialization

[Yury-Fridlyand]

Description

Rework PhysicalPlan tree serialization and deserialization. Make it scalable and extendable.
If a new plan should be serialized (a new feature is becoming supported by pagination) - it should properly overload SerializablePlan::writeExternal only.
The plan tree will be recovered in deserialization the same way it was before serialization.
New mechanism can also skip plans from serialization - for example, it skips ResourceMonitorPlan.

Issues Resolved

opensearch-project#1483

Check List

• New functionality includes testing.
  • All tests pass, including unit test, integration test and doctest
• New functionality has been documented.
  • New functionality has javadoc added
  • New functionality has user manual doc added
• Commits are signed per the DCO using --signoff

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[MaxKsyunz]

When can ClassCastException be thrown?

[Yury-Fridlyand]

We are always trying to convert a plan tree to a cursor in

opensearch-project-sql/opensearch/src/main/java/org/opensearch/sql/opensearch/executor/OpenSearchExecutionEngine.java

Line 55 in 10ba1d6

plan.getTotalHits(), paginatedPlanCache.convertToCursor(plan));

If tree contains a plan which doesn't implement SerializablePlan, there would be a ClassCastException somewhere, e.g. in

opensearch-project-sql/opensearch/src/main/java/org/opensearch/sql/opensearch/executor/protector/ResourceMonitorPlan.java

Lines 93 to 96 in 10ba1d6

	@Override
	public SerializablePlan getPlanForSerialization() {
	return (SerializablePlan) delegate;
	}

[Yury-Fridlyand]

I don't serialize PaginateOperator (to reduce cursor size), so I can't check plan instanceof PaginateOperator here as it was before.

opensearch-project-sql/core/src/main/java/org/opensearch/sql/planner/physical/PaginateOperator.java

Lines 69 to 73 in 0ff3390

	/** No need to serialize a PaginateOperator, it actually does nothing - it is a wrapper. */
	@Override
	public SerializablePlan getPlanForSerialization() {
	return (SerializablePlan) input;
	}

That means I have to do another protection here. The incoming tree could be ProjectOperator -> ResourceMonitorPlan -> PrometheusIndexScan or ProjectOperator -> ValuesOperator.

[Yury-Fridlyand]

Superseded by opensearch-project#1498