Add new physical rule CombinePartialFinalAggregate (#5837)

* add CombinePartialFinalAggregate rule

* Implement PartialEq for AggregateExpr

* fix compile error

* refine logic in the rule

* add UT

* resolve review comments

* fix compare grouping columns

datafusion/core/src/execution/context.rs

@@ -110,6 +110,7 @@ use datafusion_sql::planner::object_name_to_table_reference;
 use uuid::Uuid;
 
 // backwards compatibility
+use crate::physical_optimizer::combine_partial_final_agg::CombinePartialFinalAggregate;
 pub use datafusion_execution::config::SessionConfig;
 pub use datafusion_execution::TaskContext;
 
@@ -1329,6 +1330,9 @@ impl SessionState {
             // Note that one should always run this rule after running the EnforceDistribution rule
             // as the latter may break local sorting requirements.
             Arc::new(EnforceSorting::new()),
+            // The CombinePartialFinalAggregate rule should be applied after the EnforceDistribution
+            // and EnforceSorting rules
+            Arc::new(CombinePartialFinalAggregate::new()),
             // The CoalesceBatches rule will not influence the distribution and ordering of the
             // whole plan tree. Therefore, to avoid influencing other rules, it should run last.
             Arc::new(CoalesceBatches::new()),