feat: support for NestedLoopJoinExec in datafusion-proto (#6902)

datafusion/core/src/physical_plan/joins/nested_loop_join.rs

@@ -118,6 +118,26 @@ impl NestedLoopJoinExec {
             metrics: Default::default(),
         })
     }
+
+    /// left (build) side which gets hashed
+    pub fn left(&self) -> &Arc<dyn ExecutionPlan> {
+        &self.left
+    }
+
+    /// right (probe) side which are filtered by the hash table
+    pub fn right(&self) -> &Arc<dyn ExecutionPlan> {
+        &self.right
+    }
+
+    /// Filters applied before join output
+    pub fn filter(&self) -> Option<&JoinFilter> {
+        self.filter.as_ref()
+    }
+
+    /// How the join is performed
+    pub fn join_type(&self) -> &JoinType {
+        &self.join_type
+    }
 }
 
 impl DisplayAs for NestedLoopJoinExec {

datafusion/proto/proto/datafusion.proto

@@ -1059,6 +1059,7 @@ message PhysicalPlanNode {
     UnionExecNode union = 19;
     ExplainExecNode explain = 20;
     SortPreservingMergeExecNode sort_preserving_merge = 21;
+    NestedLoopJoinExecNode nested_loop_join = 22;
   }
 }
 
@@ -1380,6 +1381,13 @@ message SortPreservingMergeExecNode {
   int64 fetch = 3;
 }
 
+message NestedLoopJoinExecNode {
+  PhysicalPlanNode left = 1;
+  PhysicalPlanNode right = 2;
+  JoinType join_type = 3;
+  JoinFilter filter = 4;
+}
+
 message CoalesceBatchesExecNode {
   PhysicalPlanNode input = 1;
   uint32 target_batch_size = 2;