Rename insert-select redistribute code base to generic purpose

src/backend/distributed/executor/citus_custom_scan.c

@@ -182,7 +182,7 @@ CitusBeginScan(CustomScanState *node, EState *estate, int eflags)
 	node->ss.ps.qual = ExecInitQual(node->ss.ps.plan->qual, (PlanState *) node);
 
 	DistributedPlan *distributedPlan = scanState->distributedPlan;
-	if (distributedPlan->insertSelectQuery != NULL)
+	if (distributedPlan->modifyQueryViaCoordinatorOrRepartition != NULL)
 	{
 		/*
 		 * INSERT..SELECT via coordinator or re-partitioning are special because

src/backend/distributed/executor/insert_select_executor.c

@@ -30,6 +30,7 @@
 #include "distributed/distributed_planner.h"
 #include "distributed/recursive_planning.h"
 #include "distributed/relation_access_tracking.h"
+#include "distributed/repartition_executor.h"
 #include "distributed/resource_lock.h"
 #include "distributed/shardinterval_utils.h"
 #include "distributed/subplan_execution.h"
@@ -55,8 +56,6 @@
 bool EnableRepartitionedInsertSelect = true;
 
 
-static List * TwoPhaseInsertSelectTaskList(Oid targetRelationId, Query *insertSelectQuery,
-										   char *resultIdPrefix);
 static void ExecutePlanIntoRelation(Oid targetRelationId, List *insertTargetList,
 									PlannedStmt *selectPlan, EState *executorState);
 static HTAB * ExecutePlanIntoColocatedIntermediateResults(Oid targetRelationId,
@@ -67,11 +66,6 @@ static HTAB * ExecutePlanIntoColocatedIntermediateResults(Oid targetRelationId,
 static List * BuildColumnNameListFromTargetList(Oid targetRelationId,
 												List *insertTargetList);
 static int PartitionColumnIndexFromColumnList(Oid relationId, List *columnNameList);
-static List * RedistributedInsertSelectTaskList(Query *insertSelectQuery,
-												CitusTableCacheEntry *targetRelation,
-												List **redistributedResults,
-												bool useBinaryFormat);
-static int PartitionColumnIndex(List *insertTargetList, Var *partitionColumn);
 static void WrapTaskListForProjection(List *taskList, List *projectedTargetEntries);
 
 
@@ -89,7 +83,8 @@ NonPushableInsertSelectExecScan(CustomScanState *node)
 	{
 		EState *executorState = ScanStateGetExecutorState(scanState);
 		DistributedPlan *distributedPlan = scanState->distributedPlan;
-		Query *insertSelectQuery = copyObject(distributedPlan->insertSelectQuery);
+		Query *insertSelectQuery =
+			copyObject(distributedPlan->modifyQueryViaCoordinatorOrRepartition);
 		List *insertTargetList = insertSelectQuery->targetList;
 		RangeTblEntry *selectRte = ExtractSelectRangeTableEntry(insertSelectQuery);
 		RangeTblEntry *insertRte = ExtractResultRelationRTE(insertSelectQuery);
@@ -99,7 +94,8 @@ NonPushableInsertSelectExecScan(CustomScanState *node)
 		HTAB *shardStateHash = NULL;
 
 		Query *selectQuery = selectRte->subquery;
-		PlannedStmt *selectPlan = copyObject(distributedPlan->selectPlanForInsertSelect);
+		PlannedStmt *selectPlan =
+			copyObject(distributedPlan->selectPlanForModifyViaCoordinatorOrRepartition);
 
 		/*
 		 * If we are dealing with partitioned table, we also need to lock its
@@ -111,7 +107,7 @@ NonPushableInsertSelectExecScan(CustomScanState *node)
 			LockPartitionRelations(targetRelationId, RowExclusiveLock);
 		}
 
-		if (distributedPlan->insertSelectMethod == INSERT_SELECT_REPARTITION)
+		if (distributedPlan->modifyWithSelectMethod == MODIFY_WITH_SELECT_REPARTITION)
 		{
 			ereport(DEBUG1, (errmsg("performing repartitioned INSERT ... SELECT")));
 
@@ -142,9 +138,10 @@ NonPushableInsertSelectExecScan(CustomScanState *node)
 			CitusTableCacheEntry *targetRelation =
 				GetCitusTableCacheEntry(targetRelationId);
 
-			int partitionColumnIndex =
+			int distributionColumnIndex =
-				PartitionColumnIndex(insertTargetList, targetRelation->partitionColumn);
+				DistributionColumnIndex(insertTargetList,
-			if (partitionColumnIndex == -1)
+										targetRelation->partitionColumn);
+			if (distributionColumnIndex == -1)
 			{
 				char *relationName = get_rel_name(targetRelationId);
 				Oid schemaOid = get_rel_namespace(targetRelationId);
@@ -158,13 +155,13 @@ NonPushableInsertSelectExecScan(CustomScanState *node)
 			}
 
 			TargetEntry *selectPartitionTE = list_nth(selectQuery->targetList,
-													  partitionColumnIndex);
+													  distributionColumnIndex);
 			const char *partitionColumnName = selectPartitionTE->resname ?
 											  selectPartitionTE->resname : "(none)";
 
 			ereport(DEBUG2, (errmsg(
 								 "partitioning SELECT query by column index %d with name %s",
-								 partitionColumnIndex, quote_literal_cstr(
+								 distributionColumnIndex, quote_literal_cstr(
 									 partitionColumnName))));
 
 			/*
@@ -182,7 +179,7 @@ NonPushableInsertSelectExecScan(CustomScanState *node)
 
 			List **redistributedResults = RedistributeTaskListResults(distResultPrefix,
 																	  distSelectTaskList,
-																	  partitionColumnIndex,
+																	  distributionColumnIndex,
 																	  targetRelation,
 																	  binaryFormat);
 
@@ -192,7 +189,7 @@ NonPushableInsertSelectExecScan(CustomScanState *node)
 			 * target shard. Create and execute a list of tasks of form
 			 * INSERT INTO ... SELECT * FROM read_intermediate_results(...);
 			 */
-			List *taskList = RedistributedInsertSelectTaskList(insertSelectQuery,
+			List *taskList = GenerateTaskListWithRedistributedResults(insertSelectQuery,
 																	  targetRelation,
 																	  redistributedResults,
 																	  binaryFormat);
@@ -235,8 +232,9 @@ NonPushableInsertSelectExecScan(CustomScanState *node)
 				intermediateResultIdPrefix);
 
 			/* generate tasks for the INSERT..SELECT phase */
-			List *taskList = TwoPhaseInsertSelectTaskList(targetRelationId,
+			List *taskList =
-														  insertSelectQuery,
+				GenerateTaskListWithColocatedIntermediateResults(
+					targetRelationId, insertSelectQuery,
 					intermediateResultIdPrefix);
 
 			/*
@@ -298,94 +296,6 @@ NonPushableInsertSelectExecScan(CustomScanState *node)
 }
 
 
-/*
- * TwoPhaseInsertSelectTaskList generates a list of tasks for a query that
- * inserts into a target relation and selects from a set of co-located
- * intermediate results.
- */
-static List *
-TwoPhaseInsertSelectTaskList(Oid targetRelationId, Query *insertSelectQuery,
-							 char *resultIdPrefix)
-{
-	List *taskList = NIL;
-
-	/*
-	 * Make a copy of the INSERT ... SELECT. We'll repeatedly replace the
-	 * subquery of insertResultQuery for different intermediate results and
-	 * then deparse it.
-	 */
-	Query *insertResultQuery = copyObject(insertSelectQuery);
-	RangeTblEntry *insertRte = ExtractResultRelationRTE(insertResultQuery);
-	RangeTblEntry *selectRte = ExtractSelectRangeTableEntry(insertResultQuery);
-
-	CitusTableCacheEntry *targetCacheEntry = GetCitusTableCacheEntry(targetRelationId);
-	int shardCount = targetCacheEntry->shardIntervalArrayLength;
-	uint32 taskIdIndex = 1;
-	uint64 jobId = INVALID_JOB_ID;
-
-	for (int shardOffset = 0; shardOffset < shardCount; shardOffset++)
-	{
-		ShardInterval *targetShardInterval =
-			targetCacheEntry->sortedShardIntervalArray[shardOffset];
-		uint64 shardId = targetShardInterval->shardId;
-		List *columnAliasList = NIL;
-		StringInfo queryString = makeStringInfo();
-		StringInfo resultId = makeStringInfo();
-
-		/* during COPY, the shard ID is appended to the result name */
-		appendStringInfo(resultId, "%s_" UINT64_FORMAT, resultIdPrefix, shardId);
-
-		/* generate the query on the intermediate result */
-		Query *resultSelectQuery = BuildSubPlanResultQuery(insertSelectQuery->targetList,
-														   columnAliasList,
-														   resultId->data);
-
-		/* put the intermediate result query in the INSERT..SELECT */
-		selectRte->subquery = resultSelectQuery;
-
-		/* setting an alias simplifies deparsing of RETURNING */
-		if (insertRte->alias == NULL)
-		{
-			Alias *alias = makeAlias(CITUS_TABLE_ALIAS, NIL);
-			insertRte->alias = alias;
-		}
-
-		/*
-		 * Generate a query string for the query that inserts into a shard and reads
-		 * from an intermediate result.
-		 *
-		 * Since CTEs have already been converted to intermediate results, they need
-		 * to removed from the query. Otherwise, worker queries include both
-		 * intermediate results and CTEs in the query.
-		 */
-		insertResultQuery->cteList = NIL;
-		deparse_shard_query(insertResultQuery, targetRelationId, shardId, queryString);
-		ereport(DEBUG2, (errmsg("distributed statement: %s", queryString->data)));
-
-		LockShardDistributionMetadata(shardId, ShareLock);
-		List *insertShardPlacementList = ActiveShardPlacementList(shardId);
-
-		RelationShard *relationShard = CitusMakeNode(RelationShard);
-		relationShard->relationId = targetShardInterval->relationId;
-		relationShard->shardId = targetShardInterval->shardId;
-
-		Task *modifyTask = CreateBasicTask(jobId, taskIdIndex, MODIFY_TASK,
-										   queryString->data);
-		modifyTask->dependentTaskList = NIL;
-		modifyTask->anchorShardId = shardId;
-		modifyTask->taskPlacementList = insertShardPlacementList;
-		modifyTask->relationShardList = list_make1(relationShard);
-		modifyTask->replicationModel = targetCacheEntry->replicationModel;
-
-		taskList = lappend(taskList, modifyTask);
-
-		taskIdIndex++;
-	}
-
-	return taskList;
-}
-
-
 /*
  * ExecutePlanIntoColocatedIntermediateResults executes the given PlannedStmt
  * and inserts tuples into a set of intermediate results that are colocated with
@@ -529,111 +439,11 @@ IsSupportedRedistributionTarget(Oid targetRelationId)
 
 
 /*
- * RedistributedInsertSelectTaskList returns a task list to insert given
+ * DistributionColumnIndex finds the index of given distribution column in the
- * redistributedResults into the given target relation.
- * redistributedResults[shardIndex] is list of cstrings each of which is
- * a result name which should be inserted into
- * targetRelation->sortedShardIntervalArray[shardIndex].
- */
-static List *
-RedistributedInsertSelectTaskList(Query *insertSelectQuery,
-								  CitusTableCacheEntry *targetRelation,
-								  List **redistributedResults,
-								  bool useBinaryFormat)
-{
-	List *taskList = NIL;
-
-	/*
-	 * Make a copy of the INSERT ... SELECT. We'll repeatedly replace the
-	 * subquery of insertResultQuery for different intermediate results and
-	 * then deparse it.
-	 */
-	Query *insertResultQuery = copyObject(insertSelectQuery);
-	RangeTblEntry *insertRte = ExtractResultRelationRTE(insertResultQuery);
-	RangeTblEntry *selectRte = ExtractSelectRangeTableEntry(insertResultQuery);
-	List *selectTargetList = selectRte->subquery->targetList;
-	Oid targetRelationId = targetRelation->relationId;
-
-	int shardCount = targetRelation->shardIntervalArrayLength;
-	int shardOffset = 0;
-	uint32 taskIdIndex = 1;
-	uint64 jobId = INVALID_JOB_ID;
-
-	for (shardOffset = 0; shardOffset < shardCount; shardOffset++)
-	{
-		ShardInterval *targetShardInterval =
-			targetRelation->sortedShardIntervalArray[shardOffset];
-		List *resultIdList = redistributedResults[targetShardInterval->shardIndex];
-		uint64 shardId = targetShardInterval->shardId;
-		StringInfo queryString = makeStringInfo();
-
-		/* skip empty tasks */
-		if (resultIdList == NIL)
-		{
-			continue;
-		}
-
-		/* sort result ids for consistent test output */
-		List *sortedResultIds = SortList(resultIdList, pg_qsort_strcmp);
-
-		/* generate the query on the intermediate result */
-		Query *fragmentSetQuery = BuildReadIntermediateResultsArrayQuery(selectTargetList,
-																		 NIL,
-																		 sortedResultIds,
-																		 useBinaryFormat);
-
-		/* put the intermediate result query in the INSERT..SELECT */
-		selectRte->subquery = fragmentSetQuery;
-
-		/* setting an alias simplifies deparsing of RETURNING */
-		if (insertRte->alias == NULL)
-		{
-			Alias *alias = makeAlias(CITUS_TABLE_ALIAS, NIL);
-			insertRte->alias = alias;
-		}
-
-		/*
-		 * Generate a query string for the query that inserts into a shard and reads
-		 * from an intermediate result.
-		 *
-		 * Since CTEs have already been converted to intermediate results, they need
-		 * to removed from the query. Otherwise, worker queries include both
-		 * intermediate results and CTEs in the query.
-		 */
-		insertResultQuery->cteList = NIL;
-		deparse_shard_query(insertResultQuery, targetRelationId, shardId, queryString);
-		ereport(DEBUG2, (errmsg("distributed statement: %s", queryString->data)));
-
-		LockShardDistributionMetadata(shardId, ShareLock);
-		List *insertShardPlacementList = ActiveShardPlacementList(shardId);
-
-		RelationShard *relationShard = CitusMakeNode(RelationShard);
-		relationShard->relationId = targetShardInterval->relationId;
-		relationShard->shardId = targetShardInterval->shardId;
-
-		Task *modifyTask = CreateBasicTask(jobId, taskIdIndex, MODIFY_TASK,
-										   queryString->data);
-		modifyTask->dependentTaskList = NIL;
-		modifyTask->anchorShardId = shardId;
-		modifyTask->taskPlacementList = insertShardPlacementList;
-		modifyTask->relationShardList = list_make1(relationShard);
-		modifyTask->replicationModel = targetRelation->replicationModel;
-
-		taskList = lappend(taskList, modifyTask);
-
-		taskIdIndex++;
-	}
-
-	return taskList;
-}
-
-
-/*
- * PartitionColumnIndex finds the index of given partition column in the
  * given target list.
  */
-static int
+int
-PartitionColumnIndex(List *insertTargetList, Var *partitionColumn)
+DistributionColumnIndex(List *insertTargetList, Var *partitionColumn)
 {
 	TargetEntry *insertTargetEntry = NULL;
 	int targetEntryIndex = 0;

src/backend/distributed/executor/multi_server_executor.c

@@ -47,7 +47,7 @@ JobExecutorType(DistributedPlan *distributedPlan)
 {
 	Job *job = distributedPlan->workerJob;
 
-	if (distributedPlan->insertSelectQuery != NULL)
+	if (distributedPlan->modifyQueryViaCoordinatorOrRepartition != NULL)
 	{
 		/*
 		 * We go through

src/backend/distributed/executor/repartition_executor.c

@@ -0,0 +1,216 @@
+/*-------------------------------------------------------------------
+ *
+ * repartition_executor.c
+ *
+ * Definitions for public functions and types related to repartition
+ * of select query results.
+ *
+ * Copyright (c) Citus Data, Inc.
+ *-------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+#include "miscadmin.h"
+
+#include "nodes/makefuncs.h"
+#include "nodes/parsenodes.h"
+
+#include "distributed/intermediate_results.h"
+#include "distributed/listutils.h"
+#include "distributed/multi_physical_planner.h"
+#include "distributed/multi_router_planner.h"
+#include "distributed/recursive_planning.h"
+#include "distributed/repartition_executor.h"
+#include "distributed/resource_lock.h"
+
+
+/*
+ * GenerateTaskListWithColocatedIntermediateResults generates a list of tasks
+ * for a query that inserts into a target relation and selects from a set of
+ * co-located intermediate results.
+ */
+List *
+GenerateTaskListWithColocatedIntermediateResults(Oid targetRelationId,
+												 Query *
+												 modifyQueryViaCoordinatorOrRepartition,
+												 char *resultIdPrefix)
+{
+	List *taskList = NIL;
+
+	/*
+	 * Make a copy of the <MODIFY-SQL> ... SELECT. We'll repeatedly replace
+	 * the subquery of modifyResultQuery for different intermediate results and
+	 * then deparse it.
+	 */
+	Query *modifyWithResultQuery = copyObject(modifyQueryViaCoordinatorOrRepartition);
+	RangeTblEntry *insertRte = ExtractResultRelationRTE(modifyWithResultQuery);
+	RangeTblEntry *selectRte = ExtractSelectRangeTableEntry(modifyWithResultQuery);
+
+	CitusTableCacheEntry *targetCacheEntry = GetCitusTableCacheEntry(targetRelationId);
+	int shardCount = targetCacheEntry->shardIntervalArrayLength;
+	uint32 taskIdIndex = 1;
+	uint64 jobId = INVALID_JOB_ID;
+
+	for (int shardOffset = 0; shardOffset < shardCount; shardOffset++)
+	{
+		ShardInterval *targetShardInterval =
+			targetCacheEntry->sortedShardIntervalArray[shardOffset];
+		uint64 shardId = targetShardInterval->shardId;
+		List *columnAliasList = NIL;
+		StringInfo queryString = makeStringInfo();
+		StringInfo resultId = makeStringInfo();
+
+		/* during COPY, the shard ID is appended to the result name */
+		appendStringInfo(resultId, "%s_" UINT64_FORMAT, resultIdPrefix, shardId);
+
+		/* generate the query on the intermediate result */
+		Query *resultSelectQuery = BuildSubPlanResultQuery(
+			modifyQueryViaCoordinatorOrRepartition->targetList,
+			columnAliasList,
+			resultId->data);
+
+		/* put the intermediate result query in the INSERT..SELECT */
+		selectRte->subquery = resultSelectQuery;
+
+		/* setting an alias simplifies deparsing of RETURNING */
+		if (insertRte->alias == NULL)
+		{
+			Alias *alias = makeAlias(CITUS_TABLE_ALIAS, NIL);
+			insertRte->alias = alias;
+		}
+
+		/*
+		 * Generate a query string for the query that inserts into a shard and reads
+		 * from an intermediate result.
+		 *
+		 * Since CTEs have already been converted to intermediate results, they need
+		 * to removed from the query. Otherwise, worker queries include both
+		 * intermediate results and CTEs in the query.
+		 */
+		modifyWithResultQuery->cteList = NIL;
+		deparse_shard_query(modifyWithResultQuery, targetRelationId, shardId,
+							queryString);
+		ereport(DEBUG2, (errmsg("distributed statement: %s", queryString->data)));
+
+		LockShardDistributionMetadata(shardId, ShareLock);
+		List *insertShardPlacementList = ActiveShardPlacementList(shardId);
+
+		RelationShard *relationShard = CitusMakeNode(RelationShard);
+		relationShard->relationId = targetShardInterval->relationId;
+		relationShard->shardId = targetShardInterval->shardId;
+
+		Task *modifyTask = CreateBasicTask(jobId, taskIdIndex, MODIFY_TASK,
+										   queryString->data);
+		modifyTask->dependentTaskList = NIL;
+		modifyTask->anchorShardId = shardId;
+		modifyTask->taskPlacementList = insertShardPlacementList;
+		modifyTask->relationShardList = list_make1(relationShard);
+		modifyTask->replicationModel = targetCacheEntry->replicationModel;
+
+		taskList = lappend(taskList, modifyTask);
+
+		taskIdIndex++;
+	}
+
+	return taskList;
+}
+
+
+/*
+ * GenerateTaskListWithRedistributedResults returns a task list to insert given
+ * redistributedResults into the given target relation.
+ * redistributedResults[shardIndex] is list of cstrings each of which is
+ * a result name which should be inserted into
+ * targetRelation->sortedShardIntervalArray[shardIndex].
+ */
+List *
+GenerateTaskListWithRedistributedResults(Query *modifyQueryViaCoordinatorOrRepartition,
+										 CitusTableCacheEntry *targetRelation,
+										 List **redistributedResults, bool
+										 useBinaryFormat)
+{
+	List *taskList = NIL;
+
+	/*
+	 * Make a copy of the <MODIFY-SQL> ... SELECT. We'll repeatedly replace
+	 * the subquery of modifyResultQuery for different intermediate results and
+	 * then deparse it.
+	 */
+	Query *modifyResultQuery = copyObject(modifyQueryViaCoordinatorOrRepartition);
+	RangeTblEntry *insertRte = ExtractResultRelationRTE(modifyResultQuery);
+	RangeTblEntry *selectRte = ExtractSelectRangeTableEntry(modifyResultQuery);
+	List *selectTargetList = selectRte->subquery->targetList;
+	Oid targetRelationId = targetRelation->relationId;
+
+	int shardCount = targetRelation->shardIntervalArrayLength;
+	int shardOffset = 0;
+	uint32 taskIdIndex = 1;
+	uint64 jobId = INVALID_JOB_ID;
+
+	for (shardOffset = 0; shardOffset < shardCount; shardOffset++)
+	{
+		ShardInterval *targetShardInterval =
+			targetRelation->sortedShardIntervalArray[shardOffset];
+		List *resultIdList = redistributedResults[targetShardInterval->shardIndex];
+		uint64 shardId = targetShardInterval->shardId;
+		StringInfo queryString = makeStringInfo();
+
+		/* skip empty tasks */
+		if (resultIdList == NIL)
+		{
+			continue;
+		}
+
+		/* sort result ids for consistent test output */
+		List *sortedResultIds = SortList(resultIdList, pg_qsort_strcmp);
+
+		/* generate the query on the intermediate result */
+		Query *fragmentSetQuery = BuildReadIntermediateResultsArrayQuery(selectTargetList,
+																		 NIL,
+																		 sortedResultIds,
+																		 useBinaryFormat);
+
+		/* put the intermediate result query in the INSERT..SELECT */
+		selectRte->subquery = fragmentSetQuery;
+
+		/* setting an alias simplifies deparsing of RETURNING */
+		if (insertRte->alias == NULL)
+		{
+			Alias *alias = makeAlias(CITUS_TABLE_ALIAS, NIL);
+			insertRte->alias = alias;
+		}
+
+		/*
+		 * Generate a query string for the query that inserts into a shard and reads
+		 * from an intermediate result.
+		 *
+		 * Since CTEs have already been converted to intermediate results, they need
+		 * to removed from the query. Otherwise, worker queries include both
+		 * intermediate results and CTEs in the query.
+		 */
+		modifyResultQuery->cteList = NIL;
+		deparse_shard_query(modifyResultQuery, targetRelationId, shardId, queryString);
+		ereport(DEBUG2, (errmsg("distributed statement: %s", queryString->data)));
+
+		LockShardDistributionMetadata(shardId, ShareLock);
+		List *insertShardPlacementList = ActiveShardPlacementList(shardId);
+
+		RelationShard *relationShard = CitusMakeNode(RelationShard);
+		relationShard->relationId = targetShardInterval->relationId;
+		relationShard->shardId = targetShardInterval->shardId;
+
+		Task *modifyTask = CreateBasicTask(jobId, taskIdIndex, MODIFY_TASK,
+										   queryString->data);
+		modifyTask->dependentTaskList = NIL;
+		modifyTask->anchorShardId = shardId;
+		modifyTask->taskPlacementList = insertShardPlacementList;
+		modifyTask->relationShardList = list_make1(relationShard);
+		modifyTask->replicationModel = targetRelation->replicationModel;
+
+		taskList = lappend(taskList, modifyTask);
+
+		taskIdIndex++;
+	}
+
+	return taskList;
+}

src/backend/distributed/planner/insert_select_planner.c

@@ -1417,11 +1417,11 @@ CreateNonPushableInsertSelectPlan(uint64 planId, Query *parse, ParamListInfo bou
 	Assert(!repartitioned ||
 		   !GetRTEListPropertiesForQuery(selectQueryCopy)->hasSingleShardDistTable);
 
-	distributedPlan->insertSelectQuery = insertSelectQuery;
+	distributedPlan->modifyQueryViaCoordinatorOrRepartition = insertSelectQuery;
-	distributedPlan->selectPlanForInsertSelect = selectPlan;
+	distributedPlan->selectPlanForModifyViaCoordinatorOrRepartition = selectPlan;
-	distributedPlan->insertSelectMethod = repartitioned ?
+	distributedPlan->modifyWithSelectMethod = repartitioned ?
-										  INSERT_SELECT_REPARTITION :
+											  MODIFY_WITH_SELECT_REPARTITION :
-										  INSERT_SELECT_VIA_COORDINATOR;
+											  MODIFY_WITH_SELECT_VIA_COORDINATOR;
 	distributedPlan->expectResults = insertSelectQuery->returningList != NIL;
 	distributedPlan->intermediateResultIdPrefix = InsertSelectResultIdPrefix(planId);
 	distributedPlan->targetRelationId = targetRelationId;

src/backend/distributed/planner/intermediate_result_pruning.c

@@ -69,7 +69,7 @@ FindSubPlanUsages(DistributedPlan *plan)
 												SUBPLAN_ACCESS_REMOTE);
 	}
 
-	if (plan->insertSelectQuery != NULL)
+	if (plan->modifyQueryViaCoordinatorOrRepartition != NULL)
 	{
 		/* INSERT..SELECT plans currently do not have a workerJob */
 		Assert(plan->workerJob == NULL);
@@ -79,7 +79,8 @@ FindSubPlanUsages(DistributedPlan *plan)
 		 * perform pruning. We therefore require all subplans used in the
 		 * INSERT..SELECT to be available all nodes.
 		 */
-		remoteSubPlans = FindSubPlansUsedInNode((Node *) plan->insertSelectQuery,
+		remoteSubPlans =
+			FindSubPlansUsedInNode((Node *) plan->modifyQueryViaCoordinatorOrRepartition,
 								   SUBPLAN_ACCESS_ANYWHERE);
 	}
 

src/backend/distributed/planner/multi_explain.c

@@ -234,7 +234,7 @@ NonPushableInsertSelectExplainScan(CustomScanState *node, List *ancestors,
 {
 	CitusScanState *scanState = (CitusScanState *) node;
 	DistributedPlan *distributedPlan = scanState->distributedPlan;
-	Query *insertSelectQuery = distributedPlan->insertSelectQuery;
+	Query *insertSelectQuery = distributedPlan->modifyQueryViaCoordinatorOrRepartition;
 	RangeTblEntry *selectRte = ExtractSelectRangeTableEntry(insertSelectQuery);
 
 	/*
@@ -244,7 +244,8 @@ NonPushableInsertSelectExplainScan(CustomScanState *node, List *ancestors,
 	 */
 	Query *queryCopy = copyObject(selectRte->subquery);
 
-	bool repartition = distributedPlan->insertSelectMethod == INSERT_SELECT_REPARTITION;
+	bool repartition = distributedPlan->modifyWithSelectMethod ==
+					   MODIFY_WITH_SELECT_REPARTITION;
 
 
 	if (es->analyze)

src/backend/distributed/utils/citus_copyfuncs.c

@@ -127,9 +127,9 @@ CopyNodeDistributedPlan(COPYFUNC_ARGS)
 	COPY_SCALAR_FIELD(queryId);
 	COPY_NODE_FIELD(relationIdList);
 	COPY_SCALAR_FIELD(targetRelationId);
-	COPY_NODE_FIELD(insertSelectQuery);
+	COPY_NODE_FIELD(modifyQueryViaCoordinatorOrRepartition);
-	COPY_NODE_FIELD(selectPlanForInsertSelect);
+	COPY_NODE_FIELD(selectPlanForModifyViaCoordinatorOrRepartition);
-	COPY_SCALAR_FIELD(insertSelectMethod);
+	COPY_SCALAR_FIELD(modifyWithSelectMethod);
 	COPY_STRING_FIELD(intermediateResultIdPrefix);
 
 	COPY_NODE_FIELD(subPlanList);

src/backend/distributed/utils/citus_outfuncs.c

@@ -192,7 +192,9 @@ OutDistributedPlan(OUTFUNC_ARGS)
 	WRITE_UINT64_FIELD(queryId);
 	WRITE_NODE_FIELD(relationIdList);
 	WRITE_OID_FIELD(targetRelationId);
-	WRITE_NODE_FIELD(insertSelectQuery);
+	WRITE_NODE_FIELD(modifyQueryViaCoordinatorOrRepartition);
+	WRITE_NODE_FIELD(selectPlanForModifyViaCoordinatorOrRepartition);
+	WRITE_ENUM_FIELD(modifyWithSelectMethod, ModifyWithSelectMethod);
 	WRITE_STRING_FIELD(intermediateResultIdPrefix);
 
 	WRITE_NODE_FIELD(subPlanList);

src/include/distributed/multi_physical_planner.h

@@ -361,19 +361,19 @@ typedef struct JoinSequenceNode
 
 
 /*
- * InsertSelectMethod represents the method to use for INSERT INTO ... SELECT
+ * ModifyWithSelectMethod represents the method to use for INSERT INTO ... SELECT
- * queries.
+ * or MERGE type of queries.
  *
  * Note that there is a third method which is not represented here, which is
- * pushing down the INSERT INTO ... SELECT to workers. This method is executed
+ * pushing down the MERGE/INSERT INTO ... SELECT to workers. This method is
- * similar to other distributed queries and doesn't need a special execution
+ * executed similar to other distributed queries and doesn't need a special
- * code, so we don't need to represent it here.
+ * execution code, so we don't need to represent it here.
  */
-typedef enum InsertSelectMethod
+typedef enum ModifyWithSelectMethod
 {
-	INSERT_SELECT_VIA_COORDINATOR,
+	MODIFY_WITH_SELECT_VIA_COORDINATOR,
-	INSERT_SELECT_REPARTITION
+	MODIFY_WITH_SELECT_REPARTITION
-} InsertSelectMethod;
+} ModifyWithSelectMethod;
 
 
 /*
@@ -412,18 +412,22 @@ typedef struct DistributedPlan
 	Oid targetRelationId;
 
 	/*
-	 * INSERT .. SELECT via the coordinator or repartition */
+	 * Modifications performed using the output of a source query via
-	Query *insertSelectQuery;
+	 * the coordinator or repartition.
-	PlannedStmt *selectPlanForInsertSelect;
+	 */
-	InsertSelectMethod insertSelectMethod;
+	Query *modifyQueryViaCoordinatorOrRepartition;
+	PlannedStmt *selectPlanForModifyViaCoordinatorOrRepartition;
+	ModifyWithSelectMethod modifyWithSelectMethod;
 
 	/*
-	 * If intermediateResultIdPrefix is non-null, an INSERT ... SELECT
+	 * If intermediateResultIdPrefix is non-null, the source query
-	 * via the coordinator is written to a set of intermediate results
+	 * results are written to a set of intermediate results named
-	 * named according to <intermediateResultIdPrefix>_<anchorShardId>.
+	 * according to <intermediateResultIdPrefix>_<anchorShardId>.
-	 * That way we can run a distributed INSERT ... SELECT with
+	 * That way we can run a distributed modification query which
-	 * RETURNING or ON CONFLICT from the intermediate results to the
+	 * requires evaluating source query results at the coordinator.
-	 * target relation.
+	 * Once results are captured in intermediate files, modification
+	 * is done from the intermediate results into the target relation.
+	 *
 	 */
 	char *intermediateResultIdPrefix;
 

src/include/distributed/repartition_executor.h

@@ -0,0 +1,28 @@
+/*-------------------------------------------------------------------------
+ *
+ * repartition_executor.h
+ *
+ * Declarations for public functions and types related to repartition of
+ * select query results.
+ *
+ * Copyright (c) Citus Data, Inc.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef REPARTITION_EXECUTOR_H
+#define REPARTITION_EXECUTOR_H
+
+extern int DistributionColumnIndex(List *insertTargetList, Var *partitionColumn);
+extern List * GenerateTaskListWithColocatedIntermediateResults(Oid targetRelationId,
+															   Query *
+															   modifyQueryViaCoordinatorOrRepartition,
+															   char *resultIdPrefix);
+extern List * GenerateTaskListWithRedistributedResults(
+	Query *modifyQueryViaCoordinatorOrRepartition,
+	CitusTableCacheEntry *
+	targetRelation,
+	List **redistributedResults,
+	bool useBinaryFormat);
+
+#endif /* REPARTITION_EXECUTOR_H */