From f47b3a7e7d1457695b5abf8265415659a6c45f09 Mon Sep 17 00:00:00 2001
From: Hanefi Onaldi <Hanefi.Onaldi@microsoft.com>
Date: Thu, 20 Aug 2020 12:45:01 +0300
Subject: [PATCH] Remove unused parameters from round robin reordering and
 friends (#4120)

---
 .../distributed/planner/multi_physical_planner.c   | 14 +++++++-------
 .../distributed/planner/multi_router_planner.c     |  2 +-
 src/include/distributed/multi_physical_planner.h   |  6 +++++-
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/backend/distributed/planner/multi_physical_planner.c b/src/backend/distributed/planner/multi_physical_planner.c
index 07f73db88..c68c5ee93 100644
--- a/src/backend/distributed/planner/multi_physical_planner.c
+++ b/src/backend/distributed/planner/multi_physical_planner.c
@@ -209,7 +209,7 @@ static List * GreedyAssignTaskList(List *taskList);
 static Task * GreedyAssignTask(WorkerNode *workerNode, List *taskList,
 							   List *activeShardPlacementLists);
 static List * ReorderAndAssignTaskList(List *taskList,
-									   List * (*reorderFunction)(Task *, List *));
+									   ReorderFunction reorderFunction);
 static int CompareTasksByShardId(const void *leftElement, const void *rightElement);
 static List * ActiveShardPlacementLists(List *taskList);
 static List * ActivePlacementList(List *placementList);
@@ -5210,7 +5210,7 @@ List *
 FirstReplicaAssignTaskList(List *taskList)
 {
 	/* No additional reordering need take place for this algorithm */
-	List *(*reorderFunction)(Task *, List *) = NULL;
+	ReorderFunction reorderFunction = NULL;
 
 	taskList = ReorderAndAssignTaskList(taskList, reorderFunction);
 
@@ -5237,8 +5237,8 @@ RoundRobinAssignTaskList(List *taskList)
 
 /*
  * RoundRobinReorder implements the core of the round-robin assignment policy.
- * It takes a task and placement list and rotates a copy of the placement list
- * based on the latest stable transaction id provided by PostgreSQL.
+ * It takes a placement list and rotates a copy of it based on the latest stable
+ * transaction id provided by PostgreSQL.
  *
  * We prefer to use transactionId as the seed for the rotation to use the replicas
  * in the same worker node within the same transaction. This becomes more important
@@ -5251,7 +5251,7 @@ RoundRobinAssignTaskList(List *taskList)
  * where as task-assignment happens duing the planning.
  */
 List *
-RoundRobinReorder(Task *task, List *placementList)
+RoundRobinReorder(List *placementList)
 {
 	TransactionId transactionId = GetMyProcLocalTransactionId();
 	uint32 activePlacementCount = list_length(placementList);
@@ -5270,7 +5270,7 @@ RoundRobinReorder(Task *task, List *placementList)
  * by rotation or shuffling). Returns the task list with placements assigned.
  */
 static List *
-ReorderAndAssignTaskList(List *taskList, List * (*reorderFunction)(Task *, List *))
+ReorderAndAssignTaskList(List *taskList, ReorderFunction reorderFunction)
 {
 	List *assignedTaskList = NIL;
 	ListCell *taskCell = NULL;
@@ -5301,7 +5301,7 @@ ReorderAndAssignTaskList(List *taskList, List * (*reorderFunction)(Task *, List
 		{
 			if (reorderFunction != NULL)
 			{
-				placementList = reorderFunction(task, placementList);
+				placementList = reorderFunction(placementList);
 			}
 			task->taskPlacementList = placementList;
 
diff --git a/src/backend/distributed/planner/multi_router_planner.c b/src/backend/distributed/planner/multi_router_planner.c
index d6d7dd3f0..136ac8337 100644
--- a/src/backend/distributed/planner/multi_router_planner.c
+++ b/src/backend/distributed/planner/multi_router_planner.c
@@ -1817,7 +1817,7 @@ ReorderTaskPlacementsByTaskAssignmentPolicy(Job *job,
 		placementList = RemoveCoordinatorPlacement(placementList);
 
 		/* reorder the placement list */
-		List *reorderedPlacementList = RoundRobinReorder(task, placementList);
+		List *reorderedPlacementList = RoundRobinReorder(placementList);
 		task->taskPlacementList = reorderedPlacementList;
 
 		ShardPlacement *primaryPlacement = (ShardPlacement *) linitial(
diff --git a/src/include/distributed/multi_physical_planner.h b/src/include/distributed/multi_physical_planner.h
index 0a05c8a23..d13595d0f 100644
--- a/src/include/distributed/multi_physical_planner.h
+++ b/src/include/distributed/multi_physical_planner.h
@@ -507,6 +507,10 @@ typedef struct OperatorCacheEntry
 } OperatorCacheEntry;
 
 
+/* Named function pointer type for reordering Task lists */
+typedef List *(*ReorderFunction)(List *);
+
+
 /* Config variable managed via guc.c */
 extern int TaskAssignmentPolicy;
 extern bool EnableUniqueJobIds;
@@ -557,7 +561,7 @@ extern List * TaskListDifference(const List *list1, const List *list2);
 extern List * AssignAnchorShardTaskList(List *taskList);
 extern List * FirstReplicaAssignTaskList(List *taskList);
 extern List * RoundRobinAssignTaskList(List *taskList);
-extern List * RoundRobinReorder(Task *task, List *placementList);
+extern List * RoundRobinReorder(List *placementList);
 extern void SetPlacementNodeMetadata(ShardPlacement *placement, WorkerNode *workerNode);
 extern int CompareTasksByTaskId(const void *leftElement, const void *rightElement);