Simplify intermediate result pruning logic

src/backend/distributed/planner/distributed_planner.c

@@ -22,6 +22,7 @@
 #include "catalog/pg_type.h"
 #include "distributed/citus_nodefuncs.h"
 #include "distributed/citus_nodes.h"
+#include "distributed/citus_ruleutils.h"
 #include "distributed/cte_inline.h"
 #include "distributed/function_call_delegation.h"
 #include "distributed/insert_select_planner.h"
@@ -91,8 +92,6 @@ static DistributedPlan * CreateDistributedPlan(uint64 planId, Query *originalQue
 											   bool hasUnresolvedParams,
 											   PlannerRestrictionContext *
 											   plannerRestrictionContext);
-static void FinalizeDistributedPlan(DistributedPlan *plan, Query *originalQuery);
-static void RecordSubPlansUsedInPlan(DistributedPlan *plan, Query *originalQuery);
 static DeferredErrorMessage * DeferErrorIfPartitionTableNotSingleReplicated(Oid
 																			relationId);
 
@@ -955,8 +954,6 @@ CreateDistributedPlan(uint64 planId, Query *originalQuery, Query *query, ParamLi
 
 		if (distributedPlan->planningError == NULL)
 		{
-			FinalizeDistributedPlan(distributedPlan, originalQuery);
-
 			return distributedPlan;
 		}
 		else
@@ -977,8 +974,6 @@ CreateDistributedPlan(uint64 planId, Query *originalQuery, Query *query, ParamLi
 										   plannerRestrictionContext);
 		if (distributedPlan->planningError == NULL)
 		{
-			FinalizeDistributedPlan(distributedPlan, originalQuery);
-
 			return distributedPlan;
 		}
 		else
@@ -1075,8 +1070,6 @@ CreateDistributedPlan(uint64 planId, Query *originalQuery, Query *query, ParamLi
 		Assert(distributedPlan != NULL);
 		distributedPlan->subPlanList = subPlanList;
 
-		FinalizeDistributedPlan(distributedPlan, originalQuery);
-
 		return distributedPlan;
 	}
 
@@ -1087,8 +1080,6 @@ CreateDistributedPlan(uint64 planId, Query *originalQuery, Query *query, ParamLi
 	 */
 	if (IsModifyCommand(originalQuery))
 	{
-		FinalizeDistributedPlan(distributedPlan, originalQuery);
-
 		return distributedPlan;
 	}
 
@@ -1120,87 +1111,10 @@ CreateDistributedPlan(uint64 planId, Query *originalQuery, Query *query, ParamLi
 	/* distributed plan currently should always succeed or error out */
 	Assert(distributedPlan && distributedPlan->planningError == NULL);
 
-	FinalizeDistributedPlan(distributedPlan, originalQuery);
-
 	return distributedPlan;
 }
 
 
-/*
- * FinalizeDistributedPlan is the final step of distributed planning. The function
- * currently only implements some optimizations for intermediate result(s) pruning.
- */
-static void
-FinalizeDistributedPlan(DistributedPlan *plan, Query *originalQuery)
-{
-	/*
-	 * Fast path queries, we cannot have any subplans by their definition,
-	 * so skip expensive traversals.
-	 */
-	if (!plan->fastPathRouterPlan)
-	{
-		RecordSubPlansUsedInPlan(plan, originalQuery);
-	}
-}
-
-
-/*
- * RecordSubPlansUsedInPlan gets a distributed plan a queryTree, and
- * updates the usedSubPlanNodeList of the distributed plan.
- *
- * The function simply pulls all the subPlans that are used in the queryTree
- * with one exception: subPlans in the HAVING clause. The reason is explained
- * in the function.
- */
-static void
-RecordSubPlansUsedInPlan(DistributedPlan *plan, Query *originalQuery)
-{
-	Node *havingQual = originalQuery->havingQual;
-
-	/* temporarily set to NULL, we're going to restore before the function returns */
-	originalQuery->havingQual = NULL;
-
-	/*
-	 * Mark the subplans as needed on remote side. Note that this decision is revisited
-	 * on execution, when the query only consists of intermediate results.
-	 */
-	List *subplansExceptHaving = FindSubPlansUsedInNode((Node *) originalQuery);
-	UpdateUsedPlanListLocation(subplansExceptHaving, SUBPLAN_ACCESS_REMOTE);
-
-	/* do the same for HAVING part of the query */
-	List *subplansInHaving = NIL;
-	if (originalQuery->hasSubLinks &&
-		FindNodeCheck(havingQual, IsNodeSubquery))
-	{
-		subplansInHaving = FindSubPlansUsedInNode(havingQual);
-		if (plan->masterQuery)
-		{
-			/*
-			 * If we have the master query, we're sure that the result is needed locally.
-			 * Otherwise, such as router queries, the plan may not be required locally.
-			 * Note that if the query consists of only intermediate results, the executor
-			 * may still prefer to write locally.
-			 *
-			 * If any of the subplansInHaving is used in other parts of the query,
-			 * we'll later merge those subPlans and send to remote.
-			 */
-			UpdateUsedPlanListLocation(subplansInHaving, SUBPLAN_ACCESS_LOCAL);
-		}
-		else
-		{
-			UpdateUsedPlanListLocation(subplansInHaving, SUBPLAN_ACCESS_REMOTE);
-		}
-	}
-
-	/* set back the havingQual and the calculated subplans */
-	originalQuery->havingQual = havingQual;
-
-	/* merge the used subplans */
-	plan->usedSubPlanNodeList =
-		MergeUsedSubPlanLists(subplansExceptHaving, subplansInHaving);
-}
-
-
 /*
  * EnsurePartitionTableNotReplicated errors out if the infput relation is
  * a partition table and the table has a replication factor greater than
@@ -1426,6 +1340,22 @@ FinalizePlan(PlannedStmt *localPlan, DistributedPlan *distributedPlan)
 	customScan->custom_private = list_make1(distributedPlanData);
 	customScan->flags = CUSTOMPATH_SUPPORT_BACKWARD_SCAN;
 
+	/*
+	 * Fast path queries cannot have any subplans by definition, so skip
+	 * expensive traversals.
+	 */
+	if (!distributedPlan->fastPathRouterPlan)
+	{
+		/*
+		 * Record subplans used by distributed plan to make intermediate result
+		 * pruning easier.
+		 *
+		 * We do this before finalizing the plan, because the masterQuery is
+		 * rewritten by standard_planner in FinalizeNonRouterPlan.
+		 */
+		distributedPlan->usedSubPlanNodeList = FindSubPlanUsages(distributedPlan);
+	}
+
 	if (distributedPlan->masterQuery)
 	{
 		finalPlan = FinalizeNonRouterPlan(localPlan, distributedPlan, customScan);

src/backend/distributed/planner/intermediate_result_pruning.c

@@ -13,6 +13,7 @@
  */
 
 #include "distributed/citus_custom_scan.h"
+#include "distributed/citus_ruleutils.h"
 #include "distributed/intermediate_result_pruning.h"
 #include "distributed/listutils.h"
 #include "distributed/log_utils.h"
@@ -24,6 +25,8 @@
 /* controlled via GUC, used mostly for testing */
 bool LogIntermediateResults = false;
 
+
+static List * FindSubPlansUsedInNode(Node *node);
 static void AppendAllAccessedWorkerNodes(IntermediateResultsHashEntry *entry,
 										 DistributedPlan *distributedPlan,
 										 int workerNodeCount);
@@ -31,17 +34,49 @@ static List * FindAllRemoteWorkerNodesUsingSubplan(IntermediateResultsHashEntry
 static List * RemoveLocalNodeFromWorkerList(List *workerNodeList);
 static void LogIntermediateResultMulticastSummary(IntermediateResultsHashEntry *entry,
 												  List *workerNodeList);
-static bool UsedSubPlansEqual(UsedDistributedSubPlan *left,
+static void UpdateUsedPlanListLocation(List *subPlanList, int locationMask);
-							  UsedDistributedSubPlan *right);
+
-static UsedDistributedSubPlan * UsedSubPlanListMember(List *list,
+
-													  UsedDistributedSubPlan *usedPlan);
+/*
+ * FindSubPlanUsages finds the subplans used in the master query and the
+ * job query and returns them as a combined list of UsedDistributedSubPlan
+ * structs.
+ *
+ * The list may contain duplicates if the subplan is referenced multiple
+ * times.
+ */
+List *
+FindSubPlanUsages(DistributedPlan *plan)
+{
+	List *localSubPlans = NIL;
+	List *remoteSubPlans = NIL;
+
+	if (plan->masterQuery != NULL)
+	{
+		localSubPlans = FindSubPlansUsedInNode((Node *) plan->masterQuery);
+		UpdateUsedPlanListLocation(localSubPlans, SUBPLAN_ACCESS_LOCAL);
+	}
+
+	if (plan->workerJob != NULL)
+	{
+		/*
+		 * Mark the subplans as needed on remote side. Note that this decision is revisited
+		 * on execution, when the query only consists of intermediate results.
+		 */
+		remoteSubPlans = FindSubPlansUsedInNode((Node *) plan->workerJob->jobQuery);
+		UpdateUsedPlanListLocation(remoteSubPlans, SUBPLAN_ACCESS_REMOTE);
+	}
+
+	/* merge the used subplans */
+	return list_concat(localSubPlans, remoteSubPlans);
+}
 
 
 /*
  * FindSubPlansUsedInPlan finds all the subplans used by the plan by traversing
  * the input node.
  */
-List *
+static List *
 FindSubPlansUsedInNode(Node *node)
 {
 	List *rangeTableList = NIL;
@@ -75,10 +110,7 @@ FindSubPlansUsedInNode(Node *node)
 			/* the callers are responsible for setting the accurate location */
 			usedPlan->locationMask = SUBPLAN_ACCESS_NONE;
 
-			if (!UsedSubPlanListMember(usedSubPlanList, usedPlan))
+			usedSubPlanList = lappend(usedSubPlanList, usedPlan);
-			{
-				usedSubPlanList = lappend(usedSubPlanList, usedPlan);
-			}
 		}
 	}
 
@@ -117,12 +149,6 @@ RecordSubplanExecutionsOnNodes(HTAB *intermediateResultsHash,
 		IntermediateResultsHashEntry *entry = SearchIntermediateResult(
 			intermediateResultsHash, resultId);
 
-		if (usedPlan->locationMask & SUBPLAN_ACCESS_LOCAL)
-		{
-			/* subPlan needs to be written locally as the planner decided */
-			entry->writeLocalFile = true;
-		}
-
 		/*
 		 * There is no need to traverse the subplan if the intermediate result
 		 * will be written to a local file and sent to all nodes. Note that the
@@ -133,7 +159,14 @@ RecordSubplanExecutionsOnNodes(HTAB *intermediateResultsHash,
 			elog(DEBUG4, "Subplan %s is used in all workers", resultId);
 			continue;
 		}
-		else if (usedPlan->locationMask & SUBPLAN_ACCESS_REMOTE)
+
+		if (usedPlan->locationMask & SUBPLAN_ACCESS_LOCAL)
+		{
+			/* subPlan needs to be written locally as the planner decided */
+			entry->writeLocalFile = true;
+		}
+
+		if (usedPlan->locationMask & SUBPLAN_ACCESS_REMOTE)
 		{
 			/*
 			 * traverse the plan and add find all worker nodes
@@ -383,66 +416,11 @@ SearchIntermediateResult(HTAB *intermediateResultsHash, char *resultId)
 }
 
 
-/*
- * MergeUsedSubPlanLists is a utility function that merges the two input
- * UsedSubPlan lists. Existence of the items of the rightSubPlanList
- * checked in leftSubPlanList. If not found, items are added to
- * leftSubPlanList. If found, the locationMask fields are merged.
- *
- * Finally, the in-place modified leftSubPlanList is returned.
- */
-List *
-MergeUsedSubPlanLists(List *leftSubPlanList, List *rightSubPlanList)
-{
-	ListCell *rightListCell;
-
-	foreach(rightListCell, rightSubPlanList)
-	{
-		UsedDistributedSubPlan *memberOnRightList = lfirst(rightListCell);
-		UsedDistributedSubPlan *memberOnLeftList =
-			UsedSubPlanListMember(leftSubPlanList, memberOnRightList);
-
-		if (memberOnLeftList == NULL)
-		{
-			leftSubPlanList = lappend(leftSubPlanList, memberOnRightList);
-		}
-		else
-		{
-			memberOnLeftList->locationMask |= memberOnRightList->locationMask;
-		}
-	}
-
-	return leftSubPlanList;
-}
-
-
-/*
- * UsedSubPlanListMember is a utility function inspired from list_member(),
- * but operating on UsedDistributedSubPlan struct, which doesn't have equal()
- * function defined (similar to all Citus node types).
- */
-static UsedDistributedSubPlan *
-UsedSubPlanListMember(List *usedSubPlanList, UsedDistributedSubPlan *usedPlan)
-{
-	const ListCell *usedSubPlanCell;
-
-	foreach(usedSubPlanCell, usedSubPlanList)
-	{
-		if (UsedSubPlansEqual(lfirst(usedSubPlanCell), usedPlan))
-		{
-			return lfirst(usedSubPlanCell);
-		}
-	}
-
-	return NULL;
-}
-
-
 /*
  * UpdateUsedPlanListLocation is a utility function which iterates over the list
  * and updates the subPlanLocation to the input location.
  */
-void
+static void
 UpdateUsedPlanListLocation(List *subPlanList, int locationMask)
 {
 	ListCell *subPlanCell = NULL;
@@ -453,25 +431,3 @@ UpdateUsedPlanListLocation(List *subPlanList, int locationMask)
 		subPlan->locationMask |= locationMask;
 	}
 }
-
-
-/*
- * UsedSubPlansEqual is a utility function inspired from equal(),
- * but operating on UsedDistributedSubPlan struct, which doesn't have equal()
- * function defined (similar to all Citus node types).
- */
-static bool
-UsedSubPlansEqual(UsedDistributedSubPlan *left, UsedDistributedSubPlan *right)
-{
-	if (left == NULL || right == NULL)
-	{
-		return false;
-	}
-
-	if (strncmp(left->subPlanId, right->subPlanId, NAMEDATALEN) == 0)
-	{
-		return true;
-	}
-
-	return false;
-}

src/backend/distributed/planner/multi_master_planner.c

@@ -207,10 +207,6 @@ BuildSelectStatementViaStdPlanner(Query *masterQuery, List *masterTargetList,
 	remoteScan->custom_scan_tlist = copyObject(masterTargetList);
 	remoteScan->scan.plan.targetlist = copyObject(masterTargetList);
 
-	/* probably want to do this where we add sublinks to the master plan */
-	masterQuery->hasSubLinks = checkExprHasSubLink((Node *) masterQuery);
-	Assert(masterQuery->hasWindowFuncs == contain_window_function((Node *) masterQuery));
-
 	/*
 	 * We will overwrite the alias of the rangetable which describes the custom scan.
 	 * Ideally we would have set the correct column names and alias on the range table in

src/backend/distributed/planner/multi_physical_planner.c

@@ -732,6 +732,9 @@ BuildJobQuery(MultiNode *multiNode, List *dependentJobList)
 	jobQuery->hasDistinctOn = hasDistinctOn;
 	jobQuery->windowClause = windowClause;
 	jobQuery->hasWindowFuncs = hasWindowFuncs;
+	jobQuery->hasSubLinks = checkExprHasSubLink((Node *) jobQuery);
+
+	Assert(jobQuery->hasWindowFuncs == contain_window_function((Node *) jobQuery));
 
 	return jobQuery;
 }
@@ -1271,6 +1274,7 @@ QueryJoinTree(MultiNode *multiNode, List *dependentJobList, List **rangeTableLis
 																	funcColumnTypes,
 																	funcColumnTypeMods,
 																	funcCollations);
+
 			RangeTblRef *rangeTableRef = makeNode(RangeTblRef);
 
 			rangeTableRef->rtindex = list_length(*rangeTableList) + 1;
@@ -1604,6 +1608,7 @@ BuildSubqueryJobQuery(MultiNode *multiNode)
 	jobQuery->distinctClause = distinctClause;
 	jobQuery->hasWindowFuncs = hasWindowFuncs;
 	jobQuery->windowClause = windowClause;
+	jobQuery->hasSubLinks = checkExprHasSubLink((Node *) jobQuery);
 
 	return jobQuery;
 }

src/include/distributed/intermediate_result_pruning.h

@@ -20,7 +20,7 @@
 
 extern bool LogIntermediateResults;
 
-extern List * FindSubPlansUsedInNode(Node *node);
+extern List * FindSubPlanUsages(DistributedPlan *plan);
 extern List * FindAllWorkerNodesUsingSubplan(HTAB *intermediateResultsHash,
 											 char *resultId);
 extern HTAB * MakeIntermediateResultHTAB(void);
@@ -29,8 +29,4 @@ extern void RecordSubplanExecutionsOnNodes(HTAB *intermediateResultsHash,
 extern IntermediateResultsHashEntry * SearchIntermediateResult(HTAB *resultsHash,
 															   char *resultId);
 
-/* utility functions related to UsedSubPlans */
-extern List * MergeUsedSubPlanLists(List *leftSubPlanList, List *rightSubPlanList);
-extern void UpdateUsedPlanListLocation(List *subPlanList, int localtionMask);
-
 #endif /* INTERMEDIATE_RESULT_PRUNING_H */

src/test/regress/expected/multi_subquery.out

@@ -911,8 +911,16 @@ RESET citus.coordinator_aggregation_strategy;
 SELECT t1.event_type FROM events_table t1
 GROUP BY t1.event_type HAVING t1.event_type > corr(t1.value_3, t1.value_2 + (SELECT t2.value_2 FROM users_table t2 ORDER BY 1 DESC LIMIT 1))
 ORDER BY 1;
-ERROR:  result "68_1" does not exist
+ event_type
-CONTEXT:  while executing command on localhost:xxxxx
+---------------------------------------------------------------------
+          0
+          1
+          2
+          3
+          4
+          5
+(6 rows)
+
 SELECT t1.event_type FROM events_table t1
 GROUP BY t1.event_type HAVING t1.event_type * 5 > sum(distinct t1.value_3)
 ORDER BY 1;

src/test/regress/expected/window_functions.out

@@ -196,6 +196,20 @@ ORDER BY
 (6 rows)
 
 DROP VIEW users_view, window_view;
+-- window functions along with subquery in HAVING
+SELECT
+	user_id, count (user_id) OVER (PARTITION BY user_id)
+FROM
+	users_table
+GROUP BY
+	user_id HAVING avg(value_1) < (SELECT min(k_no) FROM users_ref_test_table)
+ORDER BY 1 DESC,2 DESC
+LIMIT 1;
+ user_id | count
+---------------------------------------------------------------------
+       6 |     1
+(1 row)
+
 -- window function uses columns from two different tables
 SELECT
 	DISTINCT ON (events_table.user_id, rnk) events_table.user_id, rank() OVER my_win AS rnk

src/test/regress/sql/window_functions.sql

@@ -110,6 +110,16 @@ ORDER BY
 
 DROP VIEW users_view, window_view;
 
+-- window functions along with subquery in HAVING
+SELECT
+	user_id, count (user_id) OVER (PARTITION BY user_id)
+FROM
+	users_table
+GROUP BY
+	user_id HAVING avg(value_1) < (SELECT min(k_no) FROM users_ref_test_table)
+ORDER BY 1 DESC,2 DESC
+LIMIT 1;
+
 -- window function uses columns from two different tables
 SELECT
 	DISTINCT ON (events_table.user_id, rnk) events_table.user_id, rank() OVER my_win AS rnk