Locally execute queries that don't need any data access (#3410)

* Update shardPlacement->nodeId to uint

As the source of the shardPlacement->nodeId is always workerNode->nodeId,
and that is uint32.

We had this hack because of: 0ea4e52df5 (r266421409)

And, that is gone with: 90056f7d3c (diff-c532177d74c72d3f0e7cd10e448ab3c6L1123)

So, we're safe to do it now.

* Relax the restrictions on using the local execution

Previously, whenever any local execution happens, we disabled further
commands to do any remote queries. The basic motivation for doing that
is to prevent any accesses in the same transaction block to access the
same placements over multiple sessions: one is local session the other
is remote session to the same placement.

However, the current implementation does not distinguish local accesses
being to a placement or not. For example, we could have local accesses
that only touches intermediate results. In that case, we should not
implement the same restrictions as they become useless.

So, this is a pre-requisite for executing the intermediate result only
queries locally.

* Update the error messages

As the underlying implementation has changed, reflect it in the error
messages.

* Keep track of connections to local node

With this commit, we're adding infrastructure to track if any connection
to the same local host is done or not.

The main motivation for doing this is that we've previously were more
conservative about not choosing local execution. Simply, we disallowed
local execution if any connection to any remote node is done. However,
if we want to use local execution for intermediate result only queries,
this'd be annoying because we expect all queries to touch remote node
before the final query.

Note that this approach is still limiting in Citus MX case, but for now
we can ignore that.

* Formalize the concept of Local Node

Also some minor refactoring while creating the dummy placement

* Write intermediate results locally when the results are only needed locally

Before this commit, Citus used to always broadcast all the intermediate
results to remote nodes. However, it is possible to skip pushing
the results to remote nodes always.

There are two notable cases for doing that:

   (a) When the query consists of only intermediate results
   (b) When the query is a zero shard query

In both of the above cases, we don't need to access any data on the shards. So,
it is a valuable optimization to skip pushing the results to remote nodes.

The pattern mentioned in (a) is actually a common patterns that Citus users
use in practice. For example, if you have the following query:

WITH cte_1 AS (...), cte_2 AS (....), ... cte_n (...)
SELECT ... FROM cte_1 JOIN cte_2 .... JOIN cte_n ...;

The final query could be operating only on intermediate results. With this patch,
the intermediate results of the ctes are not unnecessarily pushed to remote
nodes.

* Add specific regression tests

As there are edge cases in Citus MX and with round-robin policy,
use the same queries on those cases as well.

* Fix failure tests

By forcing not to use local execution for intermediate results since
all the tests expects the results to be pushed remotely.

* Fix flaky test

* Apply code-review feedback

Mostly style changes

* Limit the max value of pg_dist_node_seq to reserve for internal use

src/backend/distributed/citus.control

@@ -1,6 +1,6 @@
 # Citus extension
 comment = 'Citus distributed database'
-default_version = '9.2-1'
+default_version = '9.2-2'
 module_pathname = '$libdir/citus'
 relocatable = false
 schema = pg_catalog

src/backend/distributed/commands/multi_copy.c

@@ -1828,7 +1828,7 @@ CitusCopyDestReceiverStartup(DestReceiver *dest, int operation,
 	const char *nullPrintCharacter = "\\N";
 
 	/* Citus currently doesn't know how to handle COPY command locally */
-	ErrorIfLocalExecutionHappened();
+	ErrorIfTransactionAccessedPlacementsLocally();
 
 	/* look up table properties */
 	Relation distributedRelation = heap_open(tableId, RowExclusiveLock);
@@ -2910,6 +2910,11 @@ CopyGetPlacementConnection(ShardPlacement *placement, bool stopOnFailure)
 		ClaimConnectionExclusively(connection);
 	}
 
+	if (!TransactionConnectedToLocalGroup && placement->groupId == GetLocalGroupId())
+	{
+		TransactionConnectedToLocalGroup = true;
+	}
+
 	return connection;
 }
 

src/backend/distributed/commands/utility_hook.c

@@ -187,7 +187,7 @@ multi_ProcessUtility(PlannedStmt *pstmt,
 				 * Since we cannot execute EXPLAIN ANALYZE locally, we
 				 * cannot continue.
 				 */
-				ErrorIfLocalExecutionHappened();
+				ErrorIfTransactionAccessedPlacementsLocally();
 			}
 		}
 

src/backend/distributed/connection/placement_connection.c

@@ -1168,19 +1168,3 @@ ColocatedPlacementsHashCompare(const void *a, const void *b, Size keysize)
 		return 0;
 	}
 }
-
-
-/*
- * AnyConnectionAccessedPlacements simply checks the number of entries in
- * ConnectionPlacementHash. This is useful to detect whether we're in a
- * distirbuted transaction and already executed at least one command that
- * accessed to a placement.
- */
-bool
-AnyConnectionAccessedPlacements(void)
-{
-	/* this is initialized on PG_INIT */
-	Assert(ConnectionPlacementHash != NULL);
-
-	return hash_get_num_entries(ConnectionPlacementHash) > 0;
-}

src/backend/distributed/executor/adaptive_executor.c

@@ -764,8 +764,6 @@ RunLocalExecution(CitusScanState *scanState, DistributedExecution *execution)
 {
 	uint64 rowsProcessed = ExecuteLocalTaskList(scanState, execution->localTaskList);
 
-	LocalExecutionHappened = true;
-
 	/*
 	 * We're deliberately not setting execution->rowsProceessed here. The main reason
 	 * is that modifications to reference tables would end-up setting it both here
@@ -882,7 +880,7 @@ ExecuteTaskListExtended(RowModifyLevel modLevel, List *taskList,
 	 * The code-paths that rely on this function do not know how execute
 	 * commands locally.
 	 */
-	ErrorIfLocalExecutionHappened();
+	ErrorIfTransactionAccessedPlacementsLocally();
 
 	if (MultiShardConnectionType == SEQUENTIAL_CONNECTION)
 	{
@@ -1009,7 +1007,7 @@ DecideTransactionPropertiesForTaskList(RowModifyLevel modLevel, List *taskList,
 		return xactProperties;
 	}
 
-	if (LocalExecutionHappened)
+	if (TransactionAccessedLocalPlacement)
 	{
 		/*
 		 * In case localExecutionHappened, we force the executor to use 2PC.
@@ -1730,6 +1728,12 @@ AssignTasksToConnections(DistributedExecution *execution)
 				 */
 				placementExecutionReady = false;
 			}
+
+			if (!TransactionConnectedToLocalGroup && taskPlacement->groupId ==
+				GetLocalGroupId())
+			{
+				TransactionConnectedToLocalGroup = true;
+			}
 		}
 	}
 

src/backend/distributed/executor/local_executor.c

@@ -97,7 +97,8 @@
 bool EnableLocalExecution = true;
 bool LogLocalCommands = false;
 
-bool LocalExecutionHappened = false;
+bool TransactionAccessedLocalPlacement = false;
+bool TransactionConnectedToLocalGroup = false;
 
 
 static void SplitLocalAndRemotePlacements(List *taskPlacementList,
@@ -144,6 +145,17 @@ ExecuteLocalTaskList(CitusScanState *scanState, List *taskList)
 	{
 		Task *task = (Task *) lfirst(taskCell);
 
+		/*
+		 * If we have a valid shard id, a distributed table will be accessed
+		 * during execution. Record it to apply the restrictions related to
+		 * local execution.
+		 */
+		if (!TransactionAccessedLocalPlacement &&
+			task->anchorShardId != INVALID_SHARD_ID)
+		{
+			TransactionAccessedLocalPlacement = true;
+		}
+
 		PlannedStmt *localPlan = GetCachedLocalPlan(task, distributedPlan);
 
 		/*
@@ -395,7 +407,7 @@ ShouldExecuteTasksLocally(List *taskList)
 		return false;
 	}
 
-	if (LocalExecutionHappened)
+	if (TransactionAccessedLocalPlacement)
 	{
 		/*
 		 * For various reasons, including the transaction visibility
@@ -436,7 +448,7 @@ ShouldExecuteTasksLocally(List *taskList)
 		 * has happened because that'd break transaction visibility rules and
 		 * many other things.
 		 */
-		return !AnyConnectionAccessedPlacements();
+		return !TransactionConnectedToLocalGroup;
 	}
 
 	if (!singleTask)
@@ -447,7 +459,7 @@ ShouldExecuteTasksLocally(List *taskList)
 		 * execution is happening one task at a time (e.g., similar to sequential
 		 * distributed execution).
 		 */
-		Assert(!LocalExecutionHappened);
+		Assert(!TransactionAccessedLocalPlacement);
 
 		return false;
 	}
@@ -481,20 +493,20 @@ TaskAccessesLocalNode(Task *task)
 
 
 /*
- * ErrorIfLocalExecutionHappened() errors out if a local query has already been executed
+ * ErrorIfTransactionAccessedPlacementsLocally() errors out if a local query on any shard
- * in the same transaction.
+ * has already been executed in the same transaction.
  *
  * This check is required because Citus currently hasn't implemented local execution
  * infrastructure for all the commands/executors. As we implement local execution for
  * the command/executor that this function call exists, we should simply remove the check.
  */
 void
-ErrorIfLocalExecutionHappened(void)
+ErrorIfTransactionAccessedPlacementsLocally(void)
 {
-	if (LocalExecutionHappened)
+	if (TransactionAccessedLocalPlacement)
 	{
 		ereport(ERROR, (errmsg("cannot execute command because a local execution has "
-							   "already been done in the transaction"),
+							   "accessed a placement in the transaction"),
 						errhint("Try re-running the transaction with "
 								"\"SET LOCAL citus.enable_local_execution TO OFF;\""),
 						errdetail("Some parallel commands cannot be executed if a "

src/backend/distributed/executor/multi_task_tracker_executor.c

@@ -2921,7 +2921,7 @@ TaskTrackerExecScan(CustomScanState *node)
 		Job *workerJob = distributedPlan->workerJob;
 		Query *jobQuery = workerJob->jobQuery;
 
-		ErrorIfLocalExecutionHappened();
+		ErrorIfTransactionAccessedPlacementsLocally();
 		DisableLocalExecution();
 
 		if (ContainsReadIntermediateResultFunction((Node *) jobQuery))

src/backend/distributed/executor/subplan_execution.c

@@ -46,7 +46,6 @@ ExecuteSubPlans(DistributedPlan *distributedPlan)
 	HTAB *intermediateResultsHash = MakeIntermediateResultHTAB();
 	RecordSubplanExecutionsOnNodes(intermediateResultsHash, distributedPlan);
 
-
 	/*
 	 * Make sure that this transaction has a distributed transaction ID.
 	 *
@@ -61,40 +60,18 @@ ExecuteSubPlans(DistributedPlan *distributedPlan)
 		PlannedStmt *plannedStmt = subPlan->plan;
 		uint32 subPlanId = subPlan->subPlanId;
 		ParamListInfo params = NULL;
-		bool writeLocalFile = false;
 		char *resultId = GenerateResultId(planId, subPlanId);
-		List *workerNodeList =
+		List *remoteWorkerNodeList =
 			FindAllWorkerNodesUsingSubplan(intermediateResultsHash, resultId);
 
-		/*
+		IntermediateResultsHashEntry *entry =
-		 * Write intermediate results to local file only if there is no worker
+			SearchIntermediateResult(intermediateResultsHash, resultId);
-		 * node that receives them.
-		 *
-		 * This could happen in two cases:
-		 * (a) Subquery in the having
-		 * (b) The intermediate result is not used, such as RETURNING of a
-		 *     modifying CTE is not used
-		 *
-		 * For SELECT, Postgres/Citus is clever enough to not execute the CTE
-		 * if it is not used at all, but for modifications we have to execute
-		 * the queries.
-		 */
-		if (workerNodeList == NIL)
-		{
-			writeLocalFile = true;
-
-			if ((LogIntermediateResults && IsLoggableLevel(DEBUG1)) ||
-				IsLoggableLevel(DEBUG4))
-			{
-				elog(DEBUG1, "Subplan %s will be written to local file", resultId);
-			}
-		}
 
 		SubPlanLevel++;
 		EState *estate = CreateExecutorState();
-		DestReceiver *copyDest = CreateRemoteFileDestReceiver(resultId, estate,
+		DestReceiver *copyDest =
-															  workerNodeList,
+			CreateRemoteFileDestReceiver(resultId, estate, remoteWorkerNodeList,
-															  writeLocalFile);
+										 entry->writeLocalFile);
 
 		ExecutePlanIntoDestReceiver(plannedStmt, params, copyDest);
 

src/backend/distributed/planner/intermediate_result_pruning.c

@@ -24,13 +24,13 @@
 /* controlled via GUC, used mostly for testing */
 bool LogIntermediateResults = false;
 
-static List * AppendAllAccessedWorkerNodes(List *workerNodeList,
+static void AppendAllAccessedWorkerNodes(IntermediateResultsHashEntry *entry,
-										   DistributedPlan *distributedPlan,
+										 DistributedPlan *distributedPlan,
-										   int workerNodeCount);
+										 int workerNodeCount);
-static IntermediateResultsHashEntry * SearchIntermediateResult(HTAB
+static List * FindAllRemoteWorkerNodesUsingSubplan(IntermediateResultsHashEntry *entry);
-															   *intermediateResultsHash,
+static List * RemoveLocalNodeFromWorkerList(List *workerNodeList);
-															   char *resultId);
+static void LogIntermediateResultMulticastSummary(IntermediateResultsHashEntry *entry,
-
+												  List *workerNodeList);
 
 /*
  * FindSubPlansUsedInPlan finds all the subplans used by the plan by traversing
@@ -102,10 +102,9 @@ RecordSubplanExecutionsOnNodes(HTAB *intermediateResultsHash,
 			intermediateResultsHash, resultId);
 
 		/* no need to traverse the whole plan if all the workers are hit */
-		if (list_length(entry->nodeIdList) == workerNodeCount)
+		if (list_length(entry->nodeIdList) == workerNodeCount && entry->writeLocalFile)
 		{
 			elog(DEBUG4, "Subplan %s is used in all workers", resultId);
-
 			break;
 		}
 		else
@@ -117,9 +116,7 @@ RecordSubplanExecutionsOnNodes(HTAB *intermediateResultsHash,
 			 * workers will be in the node list. We can improve intermediate result
 			 * pruning by deciding which reference table shard will be accessed earlier
 			 */
-			entry->nodeIdList = AppendAllAccessedWorkerNodes(entry->nodeIdList,
+			AppendAllAccessedWorkerNodes(entry, distributedPlan, workerNodeCount);
-															 distributedPlan,
-															 workerNodeCount);
 
 			elog(DEBUG4, "Subplan %s is used in %lu", resultId, distributedPlan->planId);
 		}
@@ -142,16 +139,19 @@ RecordSubplanExecutionsOnNodes(HTAB *intermediateResultsHash,
 
 /*
  * AppendAllAccessedWorkerNodes iterates over all the tasks in a distributed plan
- * to create the list of worker nodes that can be accessed when this plan is executed.
+ * to updates the list of worker nodes that can be accessed when this plan is
+ * executed in entry. Depending on the plan, the function may give the decision for
+ * writing the results locally.
  *
  * If there are multiple placements of a Shard, all of them are considered and
  * all the workers with placements are appended to the list. This effectively
  * means that if there is a reference table access in the distributed plan, all
  * the workers will be in the resulting list.
  */
-static List *
+static void
-AppendAllAccessedWorkerNodes(List *workerNodeList, DistributedPlan *distributedPlan, int
+AppendAllAccessedWorkerNodes(IntermediateResultsHashEntry *entry,
-							 workerNodeCount)
+							 DistributedPlan *distributedPlan,
+							 int workerNodeCount)
 {
 	List *taskList = distributedPlan->workerJob->taskList;
 	ListCell *taskCell = NULL;
@@ -163,17 +163,24 @@ AppendAllAccessedWorkerNodes(List *workerNodeList, DistributedPlan *distributedP
 		foreach(placementCell, task->taskPlacementList)
 		{
 			ShardPlacement *placement = lfirst(placementCell);
-			workerNodeList = list_append_unique_int(workerNodeList, placement->nodeId);
+
+			if (placement->nodeId == LOCAL_NODE_ID)
+			{
+				entry->writeLocalFile = true;
+				continue;
+			}
+
+			entry->nodeIdList =
+				list_append_unique_int(entry->nodeIdList, placement->nodeId);
 
 			/* early return if all the workers are accessed */
-			if (list_length(workerNodeList) == workerNodeCount)
+			if (list_length(entry->nodeIdList) == workerNodeCount &&
+				entry->writeLocalFile)
 			{
-				return workerNodeList;
+				return;
 			}
 		}
 	}
-
-	return workerNodeList;
 }
 
 
@@ -203,28 +210,67 @@ MakeIntermediateResultHTAB()
 
 /*
  * FindAllWorkerNodesUsingSubplan creates a list of worker nodes that
- * may need to access subplan results.
+ * may need to access subplan results. The function also sets writeToLocalFile
+ * flag if the result should also need be written locally.
  */
 List *
 FindAllWorkerNodesUsingSubplan(HTAB *intermediateResultsHash,
 							   char *resultId)
 {
-	List *workerNodeList = NIL;
 	IntermediateResultsHashEntry *entry =
 		SearchIntermediateResult(intermediateResultsHash, resultId);
 
+	List *remoteWorkerNodes = FindAllRemoteWorkerNodesUsingSubplan(entry);
+	if (remoteWorkerNodes == NIL)
+	{
+		/*
+		 * This could happen in two cases:
+		 * (a) Subquery in the having
+		 * (b) The intermediate result is not used, such as RETURNING of a
+		 *     modifying CTE is not used
+		 *
+		 * For SELECT, Postgres/Citus is clever enough to not execute the CTE
+		 * if it is not used at all, but for modifications we have to execute
+		 * the queries.
+		 */
+		entry->writeLocalFile = true;
+	}
+
+	/*
+	 * Don't include the current worker if the result will be written to local
+	 * file as this would be very inefficient and potentially leading race
+	 * conditions while tring to write the same file twice.
+	 */
+	if (entry->writeLocalFile)
+	{
+		remoteWorkerNodes = RemoveLocalNodeFromWorkerList(remoteWorkerNodes);
+	}
+
+	LogIntermediateResultMulticastSummary(entry, remoteWorkerNodes);
+
+	return remoteWorkerNodes;
+}
+
+
+/*
+ * FindAllRemoteWorkerNodesUsingSubplan goes over the nodeIdList of the
+ * intermediate result entry, and returns a list of workerNodes that the
+ * entry should be multi-casted to. The aim of the function is to filter
+ * out nodes with LOCAL_NODE_ID.
+ */
+static List *
+FindAllRemoteWorkerNodesUsingSubplan(IntermediateResultsHashEntry *entry)
+{
+	List *workerNodeList = NIL;
+
 	ListCell *nodeIdCell = NULL;
 	foreach(nodeIdCell, entry->nodeIdList)
 	{
-		WorkerNode *workerNode = LookupNodeByNodeId(lfirst_int(nodeIdCell));
+		uint32 nodeId = lfirst_int(nodeIdCell);
-
+		WorkerNode *workerNode = LookupNodeByNodeId(nodeId);
-		workerNodeList = lappend(workerNodeList, workerNode);
+		if (workerNode != NULL)
-
-		if ((LogIntermediateResults && IsLoggableLevel(DEBUG1)) ||
-			IsLoggableLevel(DEBUG4))
 		{
-			elog(DEBUG1, "Subplan %s will be sent to %s:%d", resultId,
+			workerNodeList = lappend(workerNodeList, workerNode);
-				 workerNode->workerName, workerNode->workerPort);
 		}
 	}
 
@@ -232,13 +278,81 @@ FindAllWorkerNodesUsingSubplan(HTAB *intermediateResultsHash,
 }
 
 
+/*
+ * RemoveLocalNodeFromWorkerList goes over the input workerNode list and
+ * removes the worker node with the local group id, and returns a new list.
+ */
+static List *
+RemoveLocalNodeFromWorkerList(List *workerNodeList)
+{
+	int32 localGroupId = GetLocalGroupId();
+
+	ListCell *workerNodeCell = NULL;
+	ListCell *prev = NULL;
+	foreach(workerNodeCell, workerNodeList)
+	{
+		WorkerNode *workerNode = (WorkerNode *) lfirst(workerNodeCell);
+		if (workerNode->groupId == localGroupId)
+		{
+			return list_delete_cell(workerNodeList, workerNodeCell, prev);
+		}
+
+		prev = workerNodeCell;
+	}
+
+	return workerNodeList;
+}
+
+
+/*
+ * LogIntermediateResultMulticastSummary is a utility function to DEBUG output
+ * the decisions given on which intermediate result should be sent to which node.
+ *
+ * For details, see the function comments.
+ */
+static void
+LogIntermediateResultMulticastSummary(IntermediateResultsHashEntry *entry,
+									  List *workerNodeList)
+{
+	char *resultId = entry->key;
+
+	/*
+	 * Log a summary of decisions made for intermediate result multicast. By default
+	 * we log at level DEBUG4. When the user has set citus.log_intermediate_results
+	 * we change the log level to DEBUG1. This is mostly useful in regression tests
+	 * where we specifically want to debug this decisions, but not all DEBUG4 messages.
+	 */
+	int logLevel = DEBUG4;
+
+	if (LogIntermediateResults)
+	{
+		logLevel = DEBUG1;
+	}
+
+	if (IsLoggableLevel(logLevel))
+	{
+		if (entry->writeLocalFile)
+		{
+			elog(logLevel, "Subplan %s will be written to local file", resultId);
+		}
+
+		WorkerNode *workerNode = NULL;
+		foreach_ptr(workerNode, workerNodeList)
+		{
+			elog(logLevel, "Subplan %s will be sent to %s:%d", resultId,
+				 workerNode->workerName, workerNode->workerPort);
+		}
+	}
+}
+
+
 /*
  * SearchIntermediateResult searches through intermediateResultsHash for a given
  * intermediate result id.
  *
  * If an entry is not found, creates a new entry with sane defaults.
  */
-static IntermediateResultsHashEntry *
+IntermediateResultsHashEntry *
 SearchIntermediateResult(HTAB *intermediateResultsHash, char *resultId)
 {
 	bool found = false;
@@ -250,6 +364,7 @@ SearchIntermediateResult(HTAB *intermediateResultsHash, char *resultId)
 	if (!found)
 	{
 		entry->nodeIdList = NIL;
+		entry->writeLocalFile = false;
 	}
 
 	return entry;

src/backend/distributed/planner/multi_router_planner.c

@@ -27,6 +27,7 @@
 #include "distributed/errormessage.h"
 #include "distributed/log_utils.h"
 #include "distributed/insert_select_planner.h"
+#include "distributed/intermediate_result_pruning.h"
 #include "distributed/master_metadata_utility.h"
 #include "distributed/master_protocol.h"
 #include "distributed/metadata_cache.h"
@@ -68,6 +69,7 @@
 #include "optimizer/restrictinfo.h"
 #include "parser/parsetree.h"
 #include "parser/parse_oper.h"
+#include "postmaster/postmaster.h"
 #include "storage/lock.h"
 #include "utils/builtins.h"
 #include "utils/elog.h"
@@ -150,6 +152,7 @@ static DeferredErrorMessage * MultiRouterPlannableQuery(Query *query);
 static DeferredErrorMessage * ErrorIfQueryHasModifyingCTE(Query *queryTree);
 static RangeTblEntry * GetUpdateOrDeleteRTE(Query *query);
 static bool SelectsFromDistributedTable(List *rangeTableList, Query *query);
+static ShardPlacement * CreateDummyPlacement(void);
 static List * get_all_actual_clauses(List *restrictinfo_list);
 static int CompareInsertValuesByShardId(const void *leftElement,
 										const void *rightElement);
@@ -2214,8 +2217,6 @@ List *
 FindRouterWorkerList(List *shardIntervalList, bool shardsPresent,
 					 bool replacePrunedQueryWithDummy)
 {
-	static uint32 zeroShardQueryRoundRobin = 0;
-
 	List *workerList = NIL;
 
 	/*
@@ -2230,23 +2231,10 @@ FindRouterWorkerList(List *shardIntervalList, bool shardsPresent,
 	}
 	else if (replacePrunedQueryWithDummy)
 	{
-		List *workerNodeList = ActiveReadableWorkerNodeList();
+		ShardPlacement *dummyPlacement = CreateDummyPlacement();
-		if (workerNodeList != NIL)
+		if (dummyPlacement != NULL)
 		{
-			int workerNodeCount = list_length(workerNodeList);
-			int workerNodeIndex = zeroShardQueryRoundRobin % workerNodeCount;
-			WorkerNode *workerNode = (WorkerNode *) list_nth(workerNodeList,
-															 workerNodeIndex);
-			ShardPlacement *dummyPlacement =
-				(ShardPlacement *) CitusMakeNode(ShardPlacement);
-			dummyPlacement->nodeName = workerNode->workerName;
-			dummyPlacement->nodePort = workerNode->workerPort;
-			dummyPlacement->nodeId = workerNode->nodeId;
-			dummyPlacement->groupId = workerNode->groupId;
-
 			workerList = lappend(workerList, dummyPlacement);
-
-			zeroShardQueryRoundRobin++;
 		}
 	}
 
@@ -2254,6 +2242,52 @@ FindRouterWorkerList(List *shardIntervalList, bool shardsPresent,
 }
 
 
+/*
+ * CreateDummyPlacement creates a dummy placement that can be used for queries
+ * that don't involve any shards. The typical examples are:
+ *       (a) queries that consist of only intermediate results
+ *       (b) queries that hit zero shards (... WHERE false;)
+ *
+ * If round robin policy is set, the placement could be on any node in pg_dist_node.
+ * Else, the local node is set for the placement.
+ */
+static ShardPlacement *
+CreateDummyPlacement(void)
+{
+	static uint32 zeroShardQueryRoundRobin = 0;
+	ShardPlacement *dummyPlacement = CitusMakeNode(ShardPlacement);
+
+	if (TaskAssignmentPolicy == TASK_ASSIGNMENT_ROUND_ROBIN)
+	{
+		List *workerNodeList = ActiveReadableWorkerNodeList();
+		if (workerNodeList == NIL)
+		{
+			return NULL;
+		}
+
+		int workerNodeCount = list_length(workerNodeList);
+		int workerNodeIndex = zeroShardQueryRoundRobin % workerNodeCount;
+		WorkerNode *workerNode = (WorkerNode *) list_nth(workerNodeList,
+														 workerNodeIndex);
+		dummyPlacement->nodeName = workerNode->workerName;
+		dummyPlacement->nodePort = workerNode->workerPort;
+		dummyPlacement->nodeId = workerNode->nodeId;
+		dummyPlacement->groupId = workerNode->groupId;
+
+		zeroShardQueryRoundRobin++;
+	}
+	else
+	{
+		dummyPlacement->nodeId = LOCAL_NODE_ID;
+		dummyPlacement->nodeName = LOCAL_HOST_NAME;
+		dummyPlacement->nodePort = PostPortNumber;
+		dummyPlacement->groupId = GetLocalGroupId();
+	}
+
+	return dummyPlacement;
+}
+
+
 /*
  * RelationShardListForShardIntervalList is a utility function which gets a list of
  * shardInterval, and returns a list of RelationShard.

src/backend/distributed/sql/citus--9.2-1--9.2-2.sql

@@ -0,0 +1,2 @@
+-- reserve UINT32_MAX (4294967295) for a special node
+ALTER SEQUENCE pg_catalog.pg_dist_node_nodeid_seq MAXVALUE 4294967294;

src/backend/distributed/transaction/transaction_management.c

@@ -248,7 +248,8 @@ CoordinatedTransactionCallback(XactEvent event, void *arg)
 
 			CurrentCoordinatedTransactionState = COORD_TRANS_NONE;
 			XactModificationLevel = XACT_MODIFICATION_NONE;
-			LocalExecutionHappened = false;
+			TransactionAccessedLocalPlacement = false;
+			TransactionConnectedToLocalGroup = false;
 			dlist_init(&InProgressTransactions);
 			activeSetStmts = NULL;
 			CoordinatedTransactionUses2PC = false;
@@ -302,7 +303,8 @@ CoordinatedTransactionCallback(XactEvent event, void *arg)
 
 			CurrentCoordinatedTransactionState = COORD_TRANS_NONE;
 			XactModificationLevel = XACT_MODIFICATION_NONE;
-			LocalExecutionHappened = false;
+			TransactionAccessedLocalPlacement = false;
+			TransactionConnectedToLocalGroup = false;
 			dlist_init(&InProgressTransactions);
 			activeSetStmts = NULL;
 			CoordinatedTransactionUses2PC = false;

src/include/distributed/intermediate_result_pruning.h

@@ -13,6 +13,11 @@
 
 #include "distributed/subplan_execution.h"
 
+/*
+ * UINT32_MAX is reserved in pg_dist_node, so we can use it safely.
+ */
+#define LOCAL_NODE_ID UINT32_MAX
+
 extern bool LogIntermediateResults;
 
 extern List * FindSubPlansUsedInNode(Node *node);
@@ -21,6 +26,8 @@ extern List * FindAllWorkerNodesUsingSubplan(HTAB *intermediateResultsHash,
 extern HTAB * MakeIntermediateResultHTAB(void);
 extern void RecordSubplanExecutionsOnNodes(HTAB *intermediateResultsHash,
 										   DistributedPlan *distributedPlan);
+extern IntermediateResultsHashEntry * SearchIntermediateResult(HTAB *resultsHash,
+															   char *resultId);
 
 
 #endif /* INTERMEDIATE_RESULT_PRUNING_H */

src/include/distributed/local_executor.h

@@ -17,13 +17,14 @@
 extern bool EnableLocalExecution;
 extern bool LogLocalCommands;
 
-extern bool LocalExecutionHappened;
+extern bool TransactionAccessedLocalPlacement;
+extern bool TransactionConnectedToLocalGroup;
 
 extern uint64 ExecuteLocalTaskList(CitusScanState *scanState, List *taskList);
 extern void ExtractLocalAndRemoteTasks(bool readOnlyPlan, List *taskList,
 									   List **localTaskList, List **remoteTaskList);
 extern bool ShouldExecuteTasksLocally(List *taskList);
-extern void ErrorIfLocalExecutionHappened(void);
+extern void ErrorIfTransactionAccessedPlacementsLocally(void);
 extern void SetTaskQueryAndPlacementList(Task *task, Query *query, List *placementList);
 extern char * TaskQueryString(Task *task);
 extern bool TaskAccessesLocalNode(Task *task);

src/include/distributed/placement_connection.h

@@ -39,7 +39,6 @@ extern void CloseShardPlacementAssociation(struct MultiConnection *connection);
 extern void ResetShardPlacementAssociation(struct MultiConnection *connection);
 
 extern void InitPlacementConnectionManagement(void);
-extern bool AnyConnectionAccessedPlacements(void);
 
 extern bool ConnectionModifiedPlacement(MultiConnection *connection);
 extern bool ConnectionUsedForAnyPlacements(MultiConnection *connection);

src/include/distributed/subplan_execution.h

@@ -28,11 +28,16 @@ extern void ExecuteSubPlans(DistributedPlan *distributedPlan);
  * The nodeIdList contains a set of unique WorkerNode ids that have placements
  * that can be used in non-colocated subquery joins with the intermediate result
  * given in the key.
+ *
+ * writeLocalFile indicates if the intermediate result is accessed during local
+ * execution. Note that there can possibly be an item for the local node in the
+ * NodeIdList.
  */
 typedef struct IntermediateResultsHashEntry
 {
 	char key[NAMEDATALEN];
 	List *nodeIdList;
+	bool writeLocalFile;
 } IntermediateResultsHashEntry;
 
 #endif /* SUBPLAN_EXECUTION_H */

src/test/regress/expected/coordinator_shouldhaveshards.out

@@ -107,7 +107,7 @@ NOTICE:  executing the command locally: SELECT y FROM coordinator_shouldhaveshar
 (1 row)
 
 ALTER TABLE test DROP COLUMN z;
-ERROR:  cannot execute command because a local execution has already been done in the transaction
+ERROR:  cannot execute command because a local execution has accessed a placement in the transaction
 DETAIL:  Some parallel commands cannot be executed if a previous command has already been executed locally
 HINT:  Try re-running the transaction with "SET LOCAL citus.enable_local_execution TO OFF;"
 ROLLBACK;

src/test/regress/expected/failure_cte_subquery.out

@@ -6,6 +6,8 @@ SET citus.next_shard_id TO 16000000;
 -- CTE inlining should not happen because
 -- the tests rely on intermediate results
 SET citus.enable_cte_inlining TO false;
+-- prevent using locally executing the intermediate results
+SET citus.task_assignment_policy TO "round-robin";
 SELECT pg_backend_pid() as pid \gset
 CREATE TABLE users_table (user_id int, user_name text);
 CREATE TABLE events_table(user_id int, event_id int, event_type int);

src/test/regress/expected/fast_path_router_modify.out

@@ -368,8 +368,7 @@ EXECUTE prepared_zero_shard_select(1);
 DEBUG:  Deferred pruning for a fast-path router query
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 1) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 1) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 4
  count
 ---------------------------------------------------------------------
      0
@@ -379,8 +378,7 @@ EXECUTE prepared_zero_shard_select(2);
 DEBUG:  Deferred pruning for a fast-path router query
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 2) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 2) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 3
  count
 ---------------------------------------------------------------------
      0
@@ -390,8 +388,7 @@ EXECUTE prepared_zero_shard_select(3);
 DEBUG:  Deferred pruning for a fast-path router query
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 3) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 3) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 4
  count
 ---------------------------------------------------------------------
      0
@@ -401,8 +398,7 @@ EXECUTE prepared_zero_shard_select(4);
 DEBUG:  Deferred pruning for a fast-path router query
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 4) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 4) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 3
  count
 ---------------------------------------------------------------------
      0
@@ -412,8 +408,7 @@ EXECUTE prepared_zero_shard_select(5);
 DEBUG:  Deferred pruning for a fast-path router query
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 5) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 5) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 4
  count
 ---------------------------------------------------------------------
      0
@@ -423,16 +418,14 @@ EXECUTE prepared_zero_shard_select(6);
 DEBUG:  Deferred pruning for a fast-path router query
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 6) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 6) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 3
  count
 ---------------------------------------------------------------------
      0
 (1 row)
 
 EXECUTE prepared_zero_shard_select(7);
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 7) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 7) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 4
  count
 ---------------------------------------------------------------------
      0
@@ -466,16 +459,14 @@ EXECUTE prepared_zero_shard_update(7);
 -- same test with fast-path disabled
 SET citus.enable_fast_path_router_planner TO FALSE;
 EXECUTE prepared_zero_shard_select(1);
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 1) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 1) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 4
  count
 ---------------------------------------------------------------------
      0
 (1 row)
 
 EXECUTE prepared_zero_shard_select(2);
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 2) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) 2) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 3
  count
 ---------------------------------------------------------------------
      0
@@ -490,8 +481,7 @@ PREPARE prepared_zero_shard_update(int) AS UPDATE modify_fast_path SET value_1 =
 EXECUTE prepared_zero_shard_select(1);
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 4
  count
 ---------------------------------------------------------------------
      0
@@ -500,8 +490,7 @@ DETAIL:  on server postgres@localhost:xxxxx connectionId: 4
 EXECUTE prepared_zero_shard_select(2);
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 3
  count
 ---------------------------------------------------------------------
      0
@@ -510,8 +499,7 @@ DETAIL:  on server postgres@localhost:xxxxx connectionId: 3
 EXECUTE prepared_zero_shard_select(3);
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 4
  count
 ---------------------------------------------------------------------
      0
@@ -520,8 +508,7 @@ DETAIL:  on server postgres@localhost:xxxxx connectionId: 4
 EXECUTE prepared_zero_shard_select(4);
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 3
  count
 ---------------------------------------------------------------------
      0
@@ -530,8 +517,7 @@ DETAIL:  on server postgres@localhost:xxxxx connectionId: 3
 EXECUTE prepared_zero_shard_select(5);
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 4
  count
 ---------------------------------------------------------------------
      0
@@ -540,16 +526,14 @@ DETAIL:  on server postgres@localhost:xxxxx connectionId: 4
 EXECUTE prepared_zero_shard_select(6);
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 3
  count
 ---------------------------------------------------------------------
      0
 (1 row)
 
 EXECUTE prepared_zero_shard_select(7);
-NOTICE:  issuing SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT NULL::integer AS key, NULL::integer AS value_1, NULL::text AS value_2 WHERE false) modify_fast_path(key, value_1, value_2) WHERE ((key OPERATOR(pg_catalog.=) $1) AND false)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 3
  count
 ---------------------------------------------------------------------
      0

src/test/regress/expected/intermediate_result_pruning.out

@@ -106,7 +106,7 @@ FROM
 DEBUG:  generating subplan XXX_1 for CTE some_values_1: SELECT key, random() AS random FROM intermediate_result_pruning.table_1 WHERE (value OPERATOR(pg_catalog.=) ANY (ARRAY['3'::text, '4'::text]))
 DEBUG:  generating subplan XXX_2 for CTE some_values_2: SELECT key, random() AS random FROM (SELECT intermediate_result.key, intermediate_result.random FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, random double precision)) some_values_1
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM ((SELECT intermediate_result.key, intermediate_result.random FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, random double precision)) some_values_2 JOIN intermediate_result_pruning.table_2 USING (key)) WHERE (table_2.key OPERATOR(pg_catalog.=) 1)
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
 DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
  count
 ---------------------------------------------------------------------
@@ -291,7 +291,7 @@ DEBUG:  generating subplan XXX_1 for CTE some_values_1: SELECT key, random() AS
 DEBUG:  generating subplan XXX_2 for CTE some_values_2: SELECT some_values_1.key, random() AS random FROM ((SELECT intermediate_result.key, intermediate_result.random FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, random double precision)) some_values_1 JOIN intermediate_result_pruning.table_2 USING (key)) WHERE (some_values_1.key OPERATOR(pg_catalog.=) 1)
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.random FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, random double precision)) some_values_2
 DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
  count
 ---------------------------------------------------------------------
      0
@@ -321,7 +321,7 @@ DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS c
 DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
  count
 ---------------------------------------------------------------------
      0
@@ -350,7 +350,7 @@ DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT DISTINCT key
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM ((SELECT intermediate_result.key FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) top_cte JOIN intermediate_result_pruning.table_2 USING (key)) WHERE (table_2.key OPERATOR(pg_catalog.=) 2)
 DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
  count
 ---------------------------------------------------------------------
      0
@@ -389,8 +389,8 @@ SELECT count(*) FROM some_values_2 JOIN some_values_1 USING (key);
 DEBUG:  generating subplan XXX_1 for CTE some_values_1: SELECT key, random() AS random FROM intermediate_result_pruning.table_1 WHERE (value OPERATOR(pg_catalog.=) ANY (ARRAY['3'::text, '4'::text]))
 DEBUG:  generating subplan XXX_2 for CTE some_values_2: SELECT key, random() AS random FROM intermediate_result_pruning.table_2 WHERE (value OPERATOR(pg_catalog.=) ANY (ARRAY['3'::text, '4'::text]))
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM ((SELECT intermediate_result.key, intermediate_result.random FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, random double precision)) some_values_2 JOIN (SELECT intermediate_result.key, intermediate_result.random FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, random double precision)) some_values_1 USING (key))
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
  count
 ---------------------------------------------------------------------
      2
@@ -406,8 +406,8 @@ SELECT count(*) FROM some_values_2 JOIN some_values_1 USING (key) WHERE false;
 DEBUG:  generating subplan XXX_1 for CTE some_values_1: SELECT key, random() AS random FROM intermediate_result_pruning.table_1 WHERE (value OPERATOR(pg_catalog.=) ANY (ARRAY['3'::text, '4'::text]))
 DEBUG:  generating subplan XXX_2 for CTE some_values_2: SELECT key, random() AS random FROM intermediate_result_pruning.table_2 WHERE (value OPERATOR(pg_catalog.=) ANY (ARRAY['3'::text, '4'::text]))
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM ((SELECT intermediate_result.key, intermediate_result.random FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, random double precision)) some_values_2 JOIN (SELECT intermediate_result.key, intermediate_result.random FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, random double precision)) some_values_1 USING (key)) WHERE false
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
  count
 ---------------------------------------------------------------------
      0
@@ -428,8 +428,8 @@ FROM
 DEBUG:  generating subplan XXX_1 for CTE some_values_1: SELECT key, random() AS random FROM intermediate_result_pruning.table_1 WHERE (value OPERATOR(pg_catalog.=) ANY (ARRAY['3'::text, '4'::text]))
 DEBUG:  generating subplan XXX_2 for CTE some_values_3: SELECT key, random() AS random FROM (SELECT intermediate_result.key, intermediate_result.random FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, random double precision)) some_values_1
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.random FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, random double precision)) some_values_3
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
  count
 ---------------------------------------------------------------------
      2
@@ -481,7 +481,7 @@ DEBUG:  generating subplan XXX_4 for subquery SELECT avg((table_2.value)::intege
 DEBUG:  generating subplan XXX_5 for subquery SELECT min(table_1.value) AS min FROM (SELECT intermediate_result.avg_ev_type FROM read_intermediate_result('XXX_4'::text, 'binary'::citus_copy_format) intermediate_result(avg_ev_type numeric)) level_5, intermediate_result_pruning.table_1 WHERE ((level_5.avg_ev_type OPERATOR(pg_catalog.=) (table_1.key)::numeric) AND (table_1.key OPERATOR(pg_catalog.>) 111)) GROUP BY level_5.avg_ev_type
 DEBUG:  generating subplan XXX_6 for subquery SELECT avg((level_6.min)::integer) AS avg FROM (SELECT intermediate_result.min FROM read_intermediate_result('XXX_5'::text, 'binary'::citus_copy_format) intermediate_result(min text)) level_6, intermediate_result_pruning.table_1 WHERE (table_1.key OPERATOR(pg_catalog.=) (level_6.min)::integer) GROUP BY table_1.value
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM (SELECT intermediate_result.avg FROM read_intermediate_result('XXX_6'::text, 'binary'::citus_copy_format) intermediate_result(avg numeric)) bar
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
 DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
@@ -489,7 +489,7 @@ DEBUG:  Subplan XXX_4 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_4 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_5 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_5 will be sent to localhost:xxxxx
-DEBUG:  Subplan XXX_6 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_6 will be written to local file
  count
 ---------------------------------------------------------------------
      0
@@ -540,12 +540,12 @@ DEBUG:  generating subplan XXX_4 for subquery SELECT avg((table_2.value)::intege
 DEBUG:  generating subplan XXX_5 for subquery SELECT min(table_1.value) AS min FROM (SELECT intermediate_result.avg_ev_type FROM read_intermediate_result('XXX_4'::text, 'binary'::citus_copy_format) intermediate_result(avg_ev_type numeric)) level_5, intermediate_result_pruning.table_1 WHERE ((level_5.avg_ev_type OPERATOR(pg_catalog.=) (table_1.key)::numeric) AND (table_1.key OPERATOR(pg_catalog.=) 111)) GROUP BY level_5.avg_ev_type
 DEBUG:  generating subplan XXX_6 for subquery SELECT avg((level_6.min)::integer) AS avg FROM (SELECT intermediate_result.min FROM read_intermediate_result('XXX_5'::text, 'binary'::citus_copy_format) intermediate_result(min text)) level_6, intermediate_result_pruning.table_1 WHERE ((table_1.key OPERATOR(pg_catalog.=) (level_6.min)::integer) AND (table_1.key OPERATOR(pg_catalog.=) 4)) GROUP BY table_1.value
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM (SELECT intermediate_result.avg FROM read_intermediate_result('XXX_6'::text, 'binary'::citus_copy_format) intermediate_result(avg numeric)) bar
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
 DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_4 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_5 will be sent to localhost:xxxxx
-DEBUG:  Subplan XXX_6 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_6 will be written to local file
  count
 ---------------------------------------------------------------------
      0
@@ -559,8 +559,8 @@ INTERSECT
 DEBUG:  generating subplan XXX_1 for subquery SELECT key FROM intermediate_result_pruning.table_1 WHERE (key OPERATOR(pg_catalog.=) 1)
 DEBUG:  generating subplan XXX_2 for subquery SELECT key FROM intermediate_result_pruning.table_1 WHERE (key OPERATOR(pg_catalog.=) 2)
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT intermediate_result.key FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer) INTERSECT SELECT intermediate_result.key FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer)
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
  key
 ---------------------------------------------------------------------
 (0 rows)
@@ -587,10 +587,10 @@ DEBUG:  generating subplan XXX_2 for subquery SELECT key FROM intermediate_resul
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT intermediate_result.key FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer) INTERSECT SELECT intermediate_result.key FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer)
 DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT table_1.key FROM intermediate_result_pruning.table_1 WHERE (table_1.key OPERATOR(pg_catalog.=) 3) INTERSECT SELECT table_1.key FROM intermediate_result_pruning.table_1 WHERE (table_1.key OPERATOR(pg_catalog.=) 4)
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT cte_1.key FROM (SELECT intermediate_result.key FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_1 UNION SELECT cte_2.key FROM (SELECT intermediate_result.key FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_2
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
  key
 ---------------------------------------------------------------------
 (0 rows)
@@ -618,9 +618,9 @@ DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT count(*) AS count FROM (i
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count FROM (SELECT intermediate_result.count FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(count bigint)) cte_2
 DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
  count
 ---------------------------------------------------------------------
      0
@@ -680,8 +680,8 @@ DEBUG:  generating subplan XXX_2 for CTE raw_data: DELETE FROM intermediate_resu
 DEBUG:  generating subplan XXX_1 for subquery SELECT min(key) AS min FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) select_data WHERE (key OPERATOR(pg_catalog.>) 1)
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: DELETE FROM intermediate_result_pruning.table_2 WHERE (key OPERATOR(pg_catalog.>=) (SELECT intermediate_result.min FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(min integer))) RETURNING key, value
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) raw_data
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
 DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
  key | value
@@ -710,8 +710,8 @@ DEBUG:  generating subplan XXX_2 for CTE raw_data: DELETE FROM intermediate_resu
 DEBUG:  generating subplan XXX_1 for subquery SELECT min(key) AS min FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) select_data WHERE ((key)::double precision OPERATOR(pg_catalog.>) ((1)::double precision OPERATOR(pg_catalog.+) random()))
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: DELETE FROM intermediate_result_pruning.table_2 WHERE ((value)::integer OPERATOR(pg_catalog.>=) (SELECT intermediate_result.min FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(min integer))) RETURNING key, value
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) raw_data
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
 DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
  key | value
@@ -737,7 +737,7 @@ DEBUG:  generating subplan XXX_1 for CTE raw_data: DELETE FROM intermediate_resu
 DEBUG:  generating subplan XXX_1 for subquery SELECT min(key) AS min FROM intermediate_result_pruning.table_1 WHERE ((key)::double precision OPERATOR(pg_catalog.>) random())
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: DELETE FROM intermediate_result_pruning.table_2 WHERE (((value)::integer OPERATOR(pg_catalog.>=) (SELECT intermediate_result.min FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(min integer))) AND (key OPERATOR(pg_catalog.=) 6)) RETURNING key, value
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) raw_data
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
 DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
  key | value
 ---------------------------------------------------------------------
@@ -789,10 +789,10 @@ DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT table_1.key FROM intermed
 DEBUG:  generating subplan XXX_3 for subquery SELECT cte_1.key FROM (SELECT intermediate_result.key FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_1 UNION SELECT cte_2.key FROM (SELECT intermediate_result.key FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_2
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT key, value FROM intermediate_result_pruning.table_2 WHERE ((key OPERATOR(pg_catalog.=) 1) AND ((value)::integer OPERATOR(pg_catalog.=) ANY (SELECT intermediate_result.key FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer))))
 DEBUG:  Collecting INSERT ... SELECT results on coordinator
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
 DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
 -- same query, cte is on the FROM clause
 -- and this time the final query (and top-level intermediate result)
@@ -826,10 +826,10 @@ DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT table_1.key FROM intermed
 DEBUG:  generating subplan XXX_3 for subquery SELECT cte_1.key FROM (SELECT intermediate_result.key FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_1 UNION SELECT cte_2.key FROM (SELECT intermediate_result.key FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_2
 DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT table_2.key, table_2.value FROM intermediate_result_pruning.table_2, (SELECT intermediate_result.key FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) foo WHERE ((table_2.key OPERATOR(pg_catalog.<>) 1) AND (foo.key OPERATOR(pg_catalog.=) (table_2.value)::integer))
 DEBUG:  performing repartitioned INSERT ... SELECT
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
-DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
-DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
 DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
 DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
 -- append partitioned/heap-type

src/test/regress/expected/local_shard_execution.out

@@ -528,7 +528,7 @@ NOTICE:  executing the command locally: SELECT count(*) AS count FROM local_shar
 
 	TRUNCATE distributed_table CASCADE;
 NOTICE:  truncate cascades to table "second_distributed_table"
-ERROR:  cannot execute command because a local execution has already been done in the transaction
+ERROR:  cannot execute command because a local execution has accessed a placement in the transaction
 DETAIL:  Some parallel commands cannot be executed if a previous command has already been executed locally
 HINT:  Try re-running the transaction with "SET LOCAL citus.enable_local_execution TO OFF;"
 ROLLBACK;
@@ -543,7 +543,7 @@ NOTICE:  executing the command locally: SELECT count(*) AS count FROM local_shar
 
 	-- even no need to supply any data
 	COPY distributed_table FROM STDIN WITH CSV;
-ERROR:  cannot execute command because a local execution has already been done in the transaction
+ERROR:  cannot execute command because a local execution has accessed a placement in the transaction
 DETAIL:  Some parallel commands cannot be executed if a previous command has already been executed locally
 HINT:  Try re-running the transaction with "SET LOCAL citus.enable_local_execution TO OFF;"
 ROLLBACK;
@@ -557,7 +557,7 @@ NOTICE:  executing the command locally: SELECT count(*) AS count FROM local_shar
 (1 row)
 
 	INSERT INTO distributed_table (key) SELECT i FROM generate_series(1,10)i;
-ERROR:  cannot execute command because a local execution has already been done in the transaction
+ERROR:  cannot execute command because a local execution has accessed a placement in the transaction
 DETAIL:  Some parallel commands cannot be executed if a previous command has already been executed locally
 HINT:  Try re-running the transaction with "SET LOCAL citus.enable_local_execution TO OFF;"
 ROLLBACK;
@@ -571,7 +571,7 @@ NOTICE:  executing the command locally: SELECT count(*) AS count FROM local_shar
 (1 row)
 
 	INSERT INTO distributed_table (key) SELECT key+1 FROM distributed_table;
-ERROR:  cannot execute command because a local execution has already been done in the transaction
+ERROR:  cannot execute command because a local execution has accessed a placement in the transaction
 DETAIL:  Some parallel commands cannot be executed if a previous command has already been executed locally
 HINT:  Try re-running the transaction with "SET LOCAL citus.enable_local_execution TO OFF;"
 ROLLBACK;
@@ -586,7 +586,7 @@ BEGIN;
 	DELETE FROM distributed_table WHERE key = 1;
 NOTICE:  executing the command locally: DELETE FROM local_shard_execution.distributed_table_1470001 distributed_table WHERE (key OPERATOR(pg_catalog.=) 1)
 	EXPLAIN ANALYZE DELETE FROM distributed_table WHERE key = 1;
-ERROR:  cannot execute command because a local execution has already been done in the transaction
+ERROR:  cannot execute command because a local execution has accessed a placement in the transaction
 DETAIL:  Some parallel commands cannot be executed if a previous command has already been executed locally
 HINT:  Try re-running the transaction with "SET LOCAL citus.enable_local_execution TO OFF;"
 ROLLBACK;
@@ -686,6 +686,7 @@ distributed_local_mixed AS (SELECT * FROM reference_table WHERE key IN (SELECT k
 SELECT * FROM local_insert, distributed_local_mixed;
 NOTICE:  executing the command locally: INSERT INTO local_shard_execution.distributed_table_1470001 AS citus_table_alias (key, value, age) VALUES (1, '11'::text, 21) ON CONFLICT(key) DO UPDATE SET value = '29'::text RETURNING citus_table_alias.key, citus_table_alias.value, citus_table_alias.age
 NOTICE:  executing the command locally: SELECT key FROM local_shard_execution.reference_table_1470000 reference_table WHERE (key OPERATOR(pg_catalog.=) ANY (SELECT local_insert.key FROM (SELECT intermediate_result.key, intermediate_result.value, intermediate_result.age FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text, age bigint)) local_insert))
+NOTICE:  executing the command locally: SELECT local_insert.key, local_insert.value, local_insert.age, distributed_local_mixed.key FROM (SELECT intermediate_result.key, intermediate_result.value, intermediate_result.age FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text, age bigint)) local_insert, (SELECT intermediate_result.key FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) distributed_local_mixed
  key | value | age | key
 ---------------------------------------------------------------------
    1 | 11    |  21 |   1
@@ -732,6 +733,7 @@ WHERE
 	distributed_table.value = all_data.value AND distributed_table.key = 1
 ORDER BY
 	1 DESC;
+NOTICE:  executing the command locally: SELECT distributed_table.key FROM local_shard_execution.distributed_table_1470001 distributed_table, (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) all_data WHERE ((distributed_table.value OPERATOR(pg_catalog.=) all_data.value) AND (distributed_table.key OPERATOR(pg_catalog.=) 1)) ORDER BY distributed_table.key DESC
  key
 ---------------------------------------------------------------------
    1
@@ -1225,7 +1227,7 @@ BEGIN;
 NOTICE:  executing the command locally: DELETE FROM local_shard_execution.distributed_table_1470003 distributed_table WHERE (key OPERATOR(pg_catalog.=) 500)
 	SET LOCAL citus.task_executor_type = 'task-tracker';
 	SELECT count(*) FROM distributed_table;
-ERROR:  cannot execute command because a local execution has already been done in the transaction
+ERROR:  cannot execute command because a local execution has accessed a placement in the transaction
 DETAIL:  Some parallel commands cannot be executed if a previous command has already been executed locally
 HINT:  Try re-running the transaction with "SET LOCAL citus.enable_local_execution TO OFF;"
 ROLLBACK;
@@ -1434,6 +1436,7 @@ EXECUTE serial_prepared_local;
 -- Citus currently doesn't allow using task_assignment_policy for intermediate results
 WITH distributed_local_mixed AS (INSERT INTO reference_table VALUES (1000) RETURNING *) SELECT * FROM distributed_local_mixed;
 NOTICE:  executing the command locally: INSERT INTO local_shard_execution.reference_table_1470000 (key) VALUES (1000) RETURNING key
+NOTICE:  executing the command locally: SELECT key FROM (SELECT intermediate_result.key FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) distributed_local_mixed
  key
 ---------------------------------------------------------------------
  1000

src/test/regress/expected/locally_execute_intermediate_results.out

@@ -0,0 +1,948 @@
+CREATE SCHEMA locally_execute_intermediate_results;
+SET search_path TO locally_execute_intermediate_results;
+SET citus.log_intermediate_results TO TRUE;
+SET citus.log_local_commands TO TRUE;
+SET client_min_messages TO DEBUG1;
+SET citus.shard_count TO 4;
+SET citus.next_shard_id TO 1580000;
+SET citus.shard_replication_factor TO 1;
+SET citus.replication_model TO 'streaming';
+CREATE TABLE table_1 (key int, value text);
+DEBUG:  building index "pg_toast_xxxxx_index" on table "pg_toast_xxxxx" serially
+SELECT create_distributed_table('table_1', 'key');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+CREATE TABLE table_2 (key int, value text);
+DEBUG:  building index "pg_toast_xxxxx_index" on table "pg_toast_xxxxx" serially
+SELECT create_distributed_table('table_2', 'key');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+CREATE TABLE ref_table (key int, value text);
+DEBUG:  building index "pg_toast_xxxxx_index" on table "pg_toast_xxxxx" serially
+SELECT create_reference_table('ref_table');
+ create_reference_table
+---------------------------------------------------------------------
+
+(1 row)
+
+-- load some data
+INSERT INTO table_1    VALUES (1, '1'), (2, '2'), (3, '3'), (4, '4');
+INSERT INTO table_2    VALUES                     (3, '3'), (4, '4'), (5, '5'), (6, '6');
+INSERT INTO ref_table  VALUES (1, '1'), (2, '2'), (3, '3'), (4, '4'), (5, '5'), (6, '6');
+-- prevent PG 11 - PG 12 outputs to diverge
+-- and have a lot more CTEs recursively planned for the
+-- sake of increasing the test coverage
+SET citus.enable_cte_inlining TO false;
+-- the query cannot be executed locally, but still because of
+-- HAVING the intermediate result is written to local file as well
+WITH cte_1 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- subquery in the WHERE part of the query can be executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+table_2
+WHERE
+key > (SELECT key FROM cte_2 ORDER BY 1 LIMIT 1)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM locally_execute_intermediate_results.table_2
+DEBUG:  generating subplan XXX_3 for subquery SELECT key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2 ORDER BY key LIMIT 1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 WHERE (key OPERATOR(pg_catalog.>) (SELECT intermediate_result.key FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer))) GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+NOTICE:  executing the command locally: SELECT key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2 ORDER BY key LIMIT 1
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- subquery in the WHERE part of the query should not be executed locally
+-- because it can be pushed down with the jointree
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(key) FROM table_2)
+SELECT
+count(*)
+FROM
+table_2
+WHERE
+key > (SELECT max FROM cte_2)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT max(key) AS max FROM locally_execute_intermediate_results.table_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 WHERE (key OPERATOR(pg_catalog.>) (SELECT cte_2.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max integer)) cte_2)) GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+ count
+---------------------------------------------------------------------
+(0 rows)
+
+-- now all the intermediate results are safe to be in local files
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(key) FROM table_2),
+cte_3 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+cte_3
+WHERE
+key > (SELECT max FROM cte_2)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT max(key) AS max FROM locally_execute_intermediate_results.table_2
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT key, value FROM locally_execute_intermediate_results.table_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_3 WHERE (key OPERATOR(pg_catalog.>) (SELECT cte_2.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max integer)) cte_2)) GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+DEBUG:  Subplan XXX_3 will be written to local file
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_3 WHERE (key OPERATOR(pg_catalog.>) (SELECT cte_2.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max integer)) cte_2)) GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1))
+ count
+---------------------------------------------------------------------
+(0 rows)
+
+-- multiple CTEs are joined inside HAVING, so written to file
+-- locally, but nothing executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1 JOIN cte_2 USING (max));
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM ((SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1 JOIN (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_2 USING (max))))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- multiple CTEs are joined inside HAVING, so written to file
+-- locally, also the join tree contains only another CTE, so should be
+-- executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(value) FROM table_1),
+cte_3 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+cte_3
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1 JOIN cte_2 USING (max));
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT key, value FROM locally_execute_intermediate_results.table_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_3 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM ((SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1 JOIN (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_2 USING (max))))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+DEBUG:  Subplan XXX_3 will be written to local file
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_3 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM ((SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1 JOIN (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_2 USING (max))))
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- now, the CTE is going to be written locally,
+-- plus that is going to be read locally because
+-- of the aggragate over the cte in HAVING
+WITH cte_1 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max(max) FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for subquery SELECT max(max) AS max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max text)))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+NOTICE:  executing the command locally: SELECT max(max) AS max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- two ctes are going to be written locally and executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT * FROM table_1)
+SELECT
+count(*)
+FROM
+cte_2
+GROUP BY key
+HAVING max(value) < (SELECT max(max) FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_3 for subquery SELECT max(max) AS max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.<) (SELECT intermediate_result.max FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(max text)))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+DEBUG:  Subplan XXX_3 will be written to local file
+NOTICE:  executing the command locally: SELECT max(max) AS max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1
+NOTICE:  executing the command locally: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.<) (SELECT intermediate_result.max FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(max text)))
+ count
+---------------------------------------------------------------------
+     1
+     1
+     1
+(3 rows)
+
+-- this time the same CTE is both joined with a distributed
+-- table and used in HAVING
+-- TODO: fixed by #3396
+WITH a AS (SELECT * FROM table_1)
+SELECT count(*),
+key
+FROM a JOIN table_2 USING (key)
+GROUP BY key
+HAVING (max(table_2.value) > (SELECT value FROM a));
+DEBUG:  generating subplan XXX_1 for CTE a: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count, a.key FROM ((SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) a JOIN locally_execute_intermediate_results.table_2 USING (key)) GROUP BY a.key HAVING (max(table_2.value) OPERATOR(pg_catalog.>) (SELECT a_1.value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) a_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+ERROR:  result "31_1" does not exist
+CONTEXT:  while executing command on localhost:xxxxx
+-- this time the same CTE is both joined with a distributed
+-- table and used in HAVING -- but used in another subquery/aggregate
+-- so one more level of recursive planning
+WITH a AS (SELECT * FROM table_1)
+SELECT count(*),
+key
+FROM a JOIN table_2 USING (key)
+GROUP BY key
+HAVING (max(table_2.value) = (SELECT max(value) FROM a));
+DEBUG:  generating subplan XXX_1 for CTE a: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for subquery SELECT max(value) AS max FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) a
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count, a.key FROM ((SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) a JOIN locally_execute_intermediate_results.table_2 USING (key)) GROUP BY a.key HAVING (max(table_2.value) OPERATOR(pg_catalog.=) (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max text)))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
+NOTICE:  executing the command locally: SELECT max(value) AS max FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) a
+ count | key
+---------------------------------------------------------------------
+     1 |   4
+(1 row)
+
+-- same query as the above, without the aggragate
+WITH a AS (SELECT max(key) as key, max(value) as value FROM ref_table)
+SELECT count(*),
+key
+FROM a JOIN ref_table USING (key)
+GROUP BY key
+HAVING (max(ref_table.value) <= (SELECT value FROM a));
+ count | key
+---------------------------------------------------------------------
+     1 |   6
+(1 row)
+
+-- some edge cases around CTEs used inside other CTEs
+-- everything can be executed locally
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) FROM cte_2)
+SELECT * FROM cte_3;
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT max(key) AS max FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(max integer)) cte_3
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+NOTICE:  executing the command locally: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  Subplan XXX_3 will be written to local file
+NOTICE:  executing the command locally: SELECT max(key) AS max FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+NOTICE:  executing the command locally: SELECT max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(max integer)) cte_3
+ max
+---------------------------------------------------------------------
+   4
+(1 row)
+
+-- the join between cte_3 and table_2 has to happen remotely
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN table_2 USING (key) WHERE table_2.key = 1;
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT max(key) AS key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT cte_3.key, table_2.value FROM ((SELECT intermediate_result.key FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_3 JOIN locally_execute_intermediate_results.table_2 USING (key)) WHERE (table_2.key OPERATOR(pg_catalog.=) 1)
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+NOTICE:  executing the command locally: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+NOTICE:  executing the command locally: SELECT max(key) AS key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+ key | value
+---------------------------------------------------------------------
+(0 rows)
+
+-- the join between cte_3 and table_2 has to happen remotely
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN ref_table USING (key);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT max(key) AS key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT cte_3.key, ref_table.value FROM ((SELECT intermediate_result.key FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_3 JOIN locally_execute_intermediate_results.ref_table USING (key))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+NOTICE:  executing the command locally: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+NOTICE:  executing the command locally: SELECT max(key) AS key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+ key | value
+---------------------------------------------------------------------
+   4 | 4
+(1 row)
+
+\c - - - :worker_1_port
+-- now use the same queries on a worker
+SET search_path TO locally_execute_intermediate_results;
+SET citus.log_intermediate_results TO TRUE;
+SET citus.log_local_commands TO TRUE;
+SET client_min_messages TO DEBUG1;
+-- prevent PG 11 - PG 12 outputs to diverge
+-- and have a lot more CTEs recursively planned for the
+-- sake of increasing the test coverage
+SET citus.enable_cte_inlining TO false;
+-- the query cannot be executed locally, but still because of
+-- HAVING the intermediate result is written to local file as well
+WITH cte_1 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- On non-mx case the subquery in the WHERE part of the query can be executed locally
+-- however, on Citus MX we have this limitation where the query cannot be executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+table_2
+WHERE
+key > (SELECT key FROM cte_2 ORDER BY 1 LIMIT 1)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM locally_execute_intermediate_results.table_2
+DEBUG:  generating subplan XXX_3 for subquery SELECT key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2 ORDER BY key LIMIT 1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 WHERE (key OPERATOR(pg_catalog.>) (SELECT intermediate_result.key FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer))) GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- subquery in the WHERE part of the query should not be executed locally
+-- because it can be pushed down with the jointree
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(key) FROM table_2)
+SELECT
+count(*)
+FROM
+table_2
+WHERE
+key > (SELECT max FROM cte_2)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT max(key) AS max FROM locally_execute_intermediate_results.table_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 WHERE (key OPERATOR(pg_catalog.>) (SELECT cte_2.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max integer)) cte_2)) GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+ count
+---------------------------------------------------------------------
+(0 rows)
+
+-- although all the intermediate results are safe to be in local files
+-- we currently do not support it on Citus MX
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(key) FROM table_2),
+cte_3 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+cte_3
+WHERE
+key > (SELECT max FROM cte_2)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT max(key) AS max FROM locally_execute_intermediate_results.table_2
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT key, value FROM locally_execute_intermediate_results.table_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_3 WHERE (key OPERATOR(pg_catalog.>) (SELECT cte_2.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max integer)) cte_2)) GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+DEBUG:  Subplan XXX_3 will be written to local file
+ count
+---------------------------------------------------------------------
+(0 rows)
+
+-- multiple CTEs are joined inside HAVING, so written to file
+-- locally, but nothing executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1 JOIN cte_2 USING (max));
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM ((SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1 JOIN (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_2 USING (max))))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- multiple CTEs are joined inside HAVING, so written to file
+-- locally, also the join tree contains only another CTE, so should be
+-- executed locally, but not on an Citus MX worker
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(value) FROM table_1),
+cte_3 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+cte_3
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1 JOIN cte_2 USING (max));
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT key, value FROM locally_execute_intermediate_results.table_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_3 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM ((SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1 JOIN (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_2 USING (max))))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+DEBUG:  Subplan XXX_3 will be written to local file
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- now, the CTE is going to be written locally,
+-- plus that could have been read locally on the coordinator
+-- because of the aggragate over the cte in HAVING
+-- but not on Citus MX
+WITH cte_1 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max(max) FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for subquery SELECT max(max) AS max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max text)))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- two could have been written locally and executed locally
+-- on the coordinator, but not on the workers
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT * FROM table_1)
+SELECT
+count(*)
+FROM
+cte_2
+GROUP BY key
+HAVING max(value) < (SELECT max(max) FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_3 for subquery SELECT max(max) AS max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.<) (SELECT intermediate_result.max FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(max text)))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+DEBUG:  Subplan XXX_3 will be written to local file
+ count
+---------------------------------------------------------------------
+     1
+     1
+     1
+(3 rows)
+
+-- this time the same CTE is both joined with a distributed
+-- table and used in HAVING
+-- TODO: fixed by #3396
+WITH a AS (SELECT * FROM table_1)
+SELECT count(*),
+key
+FROM a JOIN table_2 USING (key)
+GROUP BY key
+HAVING (max(table_2.value) > (SELECT value FROM a));
+DEBUG:  generating subplan XXX_1 for CTE a: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count, a.key FROM ((SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) a JOIN locally_execute_intermediate_results.table_2 USING (key)) GROUP BY a.key HAVING (max(table_2.value) OPERATOR(pg_catalog.>) (SELECT a_1.value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) a_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+ERROR:  result "28_1" does not exist
+CONTEXT:  while executing command on localhost:xxxxx
+-- this time the same CTE is both joined with a distributed
+-- table and used in HAVING -- but used in another subquery/aggregate
+-- so one more level of recursive planning
+WITH a AS (SELECT * FROM table_1)
+SELECT count(*),
+key
+FROM a JOIN table_2 USING (key)
+GROUP BY key
+HAVING (max(table_2.value) = (SELECT max(value) FROM a));
+DEBUG:  generating subplan XXX_1 for CTE a: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for subquery SELECT max(value) AS max FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) a
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count, a.key FROM ((SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) a JOIN locally_execute_intermediate_results.table_2 USING (key)) GROUP BY a.key HAVING (max(table_2.value) OPERATOR(pg_catalog.=) (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max text)))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
+ count | key
+---------------------------------------------------------------------
+     1 |   4
+(1 row)
+
+-- same query as the above, without the aggragate
+WITH a AS (SELECT max(key) as key, max(value) as value FROM ref_table)
+SELECT count(*),
+key
+FROM a JOIN ref_table USING (key)
+GROUP BY key
+HAVING (max(ref_table.value) <= (SELECT value FROM a));
+NOTICE:  executing the command locally: WITH a AS (SELECT max(ref_table_1.key) AS key, max(ref_table_1.value) AS value FROM locally_execute_intermediate_results.ref_table_1580008 ref_table_1) SELECT count(*) AS count, a.key FROM (a JOIN locally_execute_intermediate_results.ref_table_1580008 ref_table(key, value) USING (key)) GROUP BY a.key HAVING (max(ref_table.value) OPERATOR(pg_catalog.<=) (SELECT a_1.value FROM a a_1))
+ count | key
+---------------------------------------------------------------------
+     1 |   6
+(1 row)
+
+-- some edge cases around CTEs used inside other CTEs
+-- everything could be executed locally on the coordinator,
+-- but not on the worker
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) FROM cte_2)
+SELECT * FROM cte_3;
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT max(key) AS max FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(max integer)) cte_3
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+DEBUG:  Subplan XXX_3 will be written to local file
+ max
+---------------------------------------------------------------------
+   4
+(1 row)
+
+-- the join between cte_3 and table_2 has to could have happened
+-- locally since the key = 1 resides on this node
+-- but because of the current implementation limitations we can't
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN table_2 USING (key) WHERE table_2.key = 1;
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT max(key) AS key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT cte_3.key, table_2.value FROM ((SELECT intermediate_result.key FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_3 JOIN locally_execute_intermediate_results.table_2 USING (key)) WHERE (table_2.key OPERATOR(pg_catalog.=) 1)
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+ key | value
+---------------------------------------------------------------------
+(0 rows)
+
+-- the join between cte_3 and table_2 has to cannot happen
+-- locally because the key = 2 resides on a remote node
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN table_2 USING (key) WHERE table_2.key = 2;
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT max(key) AS key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT cte_3.key, table_2.value FROM ((SELECT intermediate_result.key FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_3 JOIN locally_execute_intermediate_results.table_2 USING (key)) WHERE (table_2.key OPERATOR(pg_catalog.=) 2)
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+ key | value
+---------------------------------------------------------------------
+(0 rows)
+
+-- the join between cte_3 and ref can could have happened locally
+-- but because of the current implementation limitations we can't
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN ref_table USING (key);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT max(key) AS key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT cte_3.key, ref_table.value FROM ((SELECT intermediate_result.key FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_3 JOIN locally_execute_intermediate_results.ref_table USING (key))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+ key | value
+---------------------------------------------------------------------
+   4 | 4
+(1 row)
+
+-- finally, use round-robin policy on the workers with same set of queries
+set citus.task_assignment_policy TO "round-robin" ;
+-- the query cannot be executed locally, but still because of
+-- HAVING the intermediate result is written to local file as well
+WITH cte_1 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- On non-mx case the subquery in the WHERE part of the query can be executed locally
+-- however, on Citus MX we have this limitation where the query cannot be executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+table_2
+WHERE
+key > (SELECT key FROM cte_2 ORDER BY 1 LIMIT 1)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM locally_execute_intermediate_results.table_2
+DEBUG:  generating subplan XXX_3 for subquery SELECT key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2 ORDER BY key LIMIT 1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 WHERE (key OPERATOR(pg_catalog.>) (SELECT intermediate_result.key FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer))) GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- subquery in the WHERE part of the query should not be executed locally
+-- because it can be pushed down with the jointree
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(key) FROM table_2)
+SELECT
+count(*)
+FROM
+table_2
+WHERE
+key > (SELECT max FROM cte_2)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT max(key) AS max FROM locally_execute_intermediate_results.table_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 WHERE (key OPERATOR(pg_catalog.>) (SELECT cte_2.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max integer)) cte_2)) GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+ count
+---------------------------------------------------------------------
+(0 rows)
+
+-- although all the intermediate results are safe to be in local files
+-- we currently do not support it on Citus MX
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(key) FROM table_2),
+cte_3 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+cte_3
+WHERE
+key > (SELECT max FROM cte_2)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT max(key) AS max FROM locally_execute_intermediate_results.table_2
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT key, value FROM locally_execute_intermediate_results.table_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_3 WHERE (key OPERATOR(pg_catalog.>) (SELECT cte_2.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max integer)) cte_2)) GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+ count
+---------------------------------------------------------------------
+(0 rows)
+
+-- multiple CTEs are joined inside HAVING, so written to file
+-- locally, but nothing executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1 JOIN cte_2 USING (max));
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM ((SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1 JOIN (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_2 USING (max))))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- multiple CTEs are joined inside HAVING, so written to file
+-- locally, also the join tree contains only another CTE, so should be
+-- executed locally, but not on an Citus MX worker
+-- TODO: fixed by #3396
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(value) FROM table_1),
+cte_3 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+cte_3
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1 JOIN cte_2 USING (max));
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT key, value FROM locally_execute_intermediate_results.table_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_3 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT cte_1.max FROM ((SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1 JOIN (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_2 USING (max))))
+DEBUG:  Subplan XXX_1 will be written to local file
+DEBUG:  Subplan XXX_2 will be written to local file
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+ERROR:  result "66_1" does not exist
+CONTEXT:  while executing command on localhost:xxxxx
+-- now, the CTE is going to be written locally,
+-- plus that could have been read locally on the coordinator
+-- because of the aggragate over the cte in HAVING
+-- but not on Citus MX
+WITH cte_1 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max(max) FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for subquery SELECT max(max) AS max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM locally_execute_intermediate_results.table_2 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.>) (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max text)))
+DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
+ count
+---------------------------------------------------------------------
+     1
+     1
+(2 rows)
+
+-- two could have been written locally and executed locally
+-- on the coordinator, but not on the workers
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT * FROM table_1)
+SELECT
+count(*)
+FROM
+cte_2
+GROUP BY key
+HAVING max(value) < (SELECT max(max) FROM cte_1);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT max(value) AS max FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_3 for subquery SELECT max(max) AS max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(max text)) cte_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2 GROUP BY key HAVING (max(value) OPERATOR(pg_catalog.<) (SELECT intermediate_result.max FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(max text)))
+DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_3 will be written to local file
+ count
+---------------------------------------------------------------------
+     1
+     1
+     1
+(3 rows)
+
+-- this time the same CTE is both joined with a distributed
+-- table and used in HAVING
+-- TODO: fixed by #3396
+WITH a AS (SELECT * FROM table_1)
+SELECT count(*),
+key
+FROM a JOIN table_2 USING (key)
+GROUP BY key
+HAVING (max(table_2.value) > (SELECT value FROM a));
+DEBUG:  generating subplan XXX_1 for CTE a: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count, a.key FROM ((SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) a JOIN locally_execute_intermediate_results.table_2 USING (key)) GROUP BY a.key HAVING (max(table_2.value) OPERATOR(pg_catalog.>) (SELECT a_1.value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) a_1))
+DEBUG:  Subplan XXX_1 will be written to local file
+ERROR:  result "77_1" does not exist
+CONTEXT:  while executing command on localhost:xxxxx
+-- this time the same CTE is both joined with a distributed
+-- table and used in HAVING -- but used in another subquery/aggregate
+-- so one more level of recursive planning
+WITH a AS (SELECT * FROM table_1)
+SELECT count(*),
+key
+FROM a JOIN table_2 USING (key)
+GROUP BY key
+HAVING (max(table_2.value) = (SELECT max(value) FROM a));
+DEBUG:  generating subplan XXX_1 for CTE a: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for subquery SELECT max(value) AS max FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) a
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count, a.key FROM ((SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) a JOIN locally_execute_intermediate_results.table_2 USING (key)) GROUP BY a.key HAVING (max(table_2.value) OPERATOR(pg_catalog.=) (SELECT intermediate_result.max FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(max text)))
+DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be written to local file
+ count | key
+---------------------------------------------------------------------
+     1 |   4
+(1 row)
+
+-- same query as the above, without the aggragate
+WITH a AS (SELECT max(key) as key, max(value) as value FROM ref_table)
+SELECT count(*),
+key
+FROM a JOIN ref_table USING (key)
+GROUP BY key
+HAVING (max(ref_table.value) <= (SELECT value FROM a));
+NOTICE:  executing the command locally: WITH a AS (SELECT max(ref_table_1.key) AS key, max(ref_table_1.value) AS value FROM locally_execute_intermediate_results.ref_table_1580008 ref_table_1) SELECT count(*) AS count, a.key FROM (a JOIN locally_execute_intermediate_results.ref_table_1580008 ref_table(key, value) USING (key)) GROUP BY a.key HAVING (max(ref_table.value) OPERATOR(pg_catalog.<=) (SELECT a_1.value FROM a a_1))
+ count | key
+---------------------------------------------------------------------
+     1 |   6
+(1 row)
+
+-- some edge cases around CTEs used inside other CTEs
+-- everything could be executed locally on the coordinator,
+-- but not on the worker
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) FROM cte_2)
+SELECT * FROM cte_3;
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT max(key) AS max FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT max FROM (SELECT intermediate_result.max FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(max integer)) cte_3
+DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+ max
+---------------------------------------------------------------------
+   4
+(1 row)
+
+-- the join between cte_3 and table_2 has to could have happened
+-- locally since the key = 1 resides on this node
+-- but because of the current implementation limitations we can't
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN table_2 USING (key) WHERE table_2.key = 1;
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT max(key) AS key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT cte_3.key, table_2.value FROM ((SELECT intermediate_result.key FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_3 JOIN locally_execute_intermediate_results.table_2 USING (key)) WHERE (table_2.key OPERATOR(pg_catalog.=) 1)
+DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+ key | value
+---------------------------------------------------------------------
+(0 rows)
+
+-- the join between cte_3 and table_2 has to cannot happen
+-- locally because the key = 2 resides on a remote node
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN table_2 USING (key) WHERE table_2.key = 2;
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT max(key) AS key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT cte_3.key, table_2.value FROM ((SELECT intermediate_result.key FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_3 JOIN locally_execute_intermediate_results.table_2 USING (key)) WHERE (table_2.key OPERATOR(pg_catalog.=) 2)
+DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+ key | value
+---------------------------------------------------------------------
+(0 rows)
+
+-- the join between cte_3 and ref can could have happened locally
+-- but because of the current implementation limitations we can't
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN ref_table USING (key);
+DEBUG:  generating subplan XXX_1 for CTE cte_1: SELECT key, value FROM locally_execute_intermediate_results.table_1
+DEBUG:  generating subplan XXX_2 for CTE cte_2: SELECT key, value FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_1
+DEBUG:  generating subplan XXX_3 for CTE cte_3: SELECT max(key) AS key FROM (SELECT intermediate_result.key, intermediate_result.value FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(key integer, value text)) cte_2
+DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT cte_3.key, ref_table.value FROM ((SELECT intermediate_result.key FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(key integer)) cte_3 JOIN locally_execute_intermediate_results.ref_table USING (key))
+DEBUG:  Subplan XXX_1 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_2 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+DEBUG:  Subplan XXX_3 will be sent to localhost:xxxxx
+ key | value
+---------------------------------------------------------------------
+   4 | 4
+(1 row)
+
+\c - - - :master_port
+SET client_min_messages TO ERROR;
+DROP SCHEMA locally_execute_intermediate_results CASCADE;

src/test/regress/expected/multi_router_planner.out

@@ -1732,7 +1732,7 @@ SELECT * FROM articles_range where author_id = 1;
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
 NOTICE:  issuing SELECT id, author_id, title, word_count FROM public.articles_range_840012 articles_range WHERE (author_id OPERATOR(pg_catalog.=) 1)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 1
+DETAIL:  on server postgres@localhost:xxxxx connectionId: 2
  id | author_id | title | word_count
 ---------------------------------------------------------------------
 (0 rows)
@@ -1741,7 +1741,7 @@ SELECT * FROM articles_range where author_id = 1 or author_id = 5;
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
 NOTICE:  issuing SELECT id, author_id, title, word_count FROM public.articles_range_840012 articles_range WHERE ((author_id OPERATOR(pg_catalog.=) 1) OR (author_id OPERATOR(pg_catalog.=) 5))
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 1
+DETAIL:  on server postgres@localhost:xxxxx connectionId: 2
  id | author_id | title | word_count
 ---------------------------------------------------------------------
 (0 rows)
@@ -1750,8 +1750,7 @@ DETAIL:  on server postgres@localhost:xxxxx connectionId: 1
 SELECT * FROM articles_range where author_id = 1 and author_id = 2;
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT id, author_id, title, word_count FROM (SELECT NULL::bigint AS id, NULL::bigint AS author_id, NULL::character varying(20) AS title, NULL::integer AS word_count WHERE false) articles_range(id, author_id, title, word_count) WHERE ((author_id OPERATOR(pg_catalog.=) 1) AND (author_id OPERATOR(pg_catalog.=) 2))
+NOTICE:  executing the command locally: SELECT id, author_id, title, word_count FROM (SELECT NULL::bigint AS id, NULL::bigint AS author_id, NULL::character varying(20) AS title, NULL::integer AS word_count WHERE false) articles_range(id, author_id, title, word_count) WHERE ((author_id OPERATOR(pg_catalog.=) 1) AND (author_id OPERATOR(pg_catalog.=) 2))
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 2
  id | author_id | title | word_count
 ---------------------------------------------------------------------
 (0 rows)
@@ -1762,7 +1761,7 @@ SELECT * FROM articles_range ar join authors_range au on (ar.author_id = au.id)
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
 NOTICE:  issuing SELECT ar.id, ar.author_id, ar.title, ar.word_count, au.name, au.id FROM (public.articles_range_840012 ar JOIN public.authors_range_840008 au ON ((ar.author_id OPERATOR(pg_catalog.=) au.id))) WHERE (ar.author_id OPERATOR(pg_catalog.=) 1)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 1
+DETAIL:  on server postgres@localhost:xxxxx connectionId: 2
  id | author_id | title | word_count | name | id
 ---------------------------------------------------------------------
 (0 rows)
@@ -1772,8 +1771,7 @@ SELECT * FROM articles_range ar join authors_range au on (ar.author_id = au.id)
 	WHERE ar.author_id = 1 and au.id = 2;
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
-NOTICE:  issuing SELECT ar.id, ar.author_id, ar.title, ar.word_count, au.name, au.id FROM ((SELECT NULL::bigint AS id, NULL::bigint AS author_id, NULL::character varying(20) AS title, NULL::integer AS word_count WHERE false) ar(id, author_id, title, word_count) JOIN (SELECT NULL::character varying(20) AS name, NULL::bigint AS id WHERE false) au(name, id) ON ((ar.author_id OPERATOR(pg_catalog.=) au.id))) WHERE ((ar.author_id OPERATOR(pg_catalog.=) 1) AND (au.id OPERATOR(pg_catalog.=) 2))
+NOTICE:  executing the command locally: SELECT ar.id, ar.author_id, ar.title, ar.word_count, au.name, au.id FROM ((SELECT NULL::bigint AS id, NULL::bigint AS author_id, NULL::character varying(20) AS title, NULL::integer AS word_count WHERE false) ar(id, author_id, title, word_count) JOIN (SELECT NULL::character varying(20) AS name, NULL::bigint AS id WHERE false) au(name, id) ON ((ar.author_id OPERATOR(pg_catalog.=) au.id))) WHERE ((ar.author_id OPERATOR(pg_catalog.=) 1) AND (au.id OPERATOR(pg_catalog.=) 2))
-DETAIL:  on server postgres@localhost:xxxxx connectionId: 1
  id | author_id | title | word_count | name | id
 ---------------------------------------------------------------------
 (0 rows)

src/test/regress/expected/set_operation_and_local_tables.out

@@ -81,7 +81,6 @@ DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT intermediate_
 DEBUG:  Creating router plan
 DEBUG:  Plan is router executable
 ERROR:  division by zero
-CONTEXT:  while executing command on localhost:xxxxx
 -- we should be able to run set operations with generate series and local tables as well
 ((SELECT x FROM local_test) UNION ALL (SELECT x FROM test)) INTERSECT (SELECT i FROM generate_series(0, 100) i) ORDER BY 1 DESC;
 DEBUG:  Local tables cannot be used in distributed queries.

src/test/regress/expected/subquery_complex_target_list.out

@@ -5,6 +5,9 @@
 CREATE SCHEMA subquery_complex;
 SET search_path TO subquery_complex, public;
 SET client_min_messages TO DEBUG1;
+-- the logs are enabled and it sometimes
+-- lead to flaky outputs when jit enabled
+SET jit_above_cost TO -1;
 -- COUNT DISTINCT at the top level query
 SELECT
   event_type, count(distinct value_2)

src/test/regress/expected/with_basics.out

@@ -101,7 +101,6 @@ WITH cte AS (
 )
 SELECT (SELECT * FROM cte);
 ERROR:  more than one row returned by a subquery used as an expression
-CONTEXT:  while executing command on localhost:xxxxx
 WITH cte_basic AS (
 	SELECT user_id FROM users_table WHERE user_id = 1
 )

src/test/regress/multi_mx_schedule

@@ -44,6 +44,7 @@ test: multi_mx_modifying_xacts
 test: multi_mx_explain
 test: multi_mx_reference_table
 test: multi_mx_insert_select_repartition
+test: locally_execute_intermediate_results
 
 # test that no tests leaked intermediate results. This should always be last
 test: ensure_no_intermediate_data_leak

src/test/regress/sql/failure_cte_subquery.sql

@@ -9,6 +9,9 @@ SET citus.next_shard_id TO 16000000;
 -- the tests rely on intermediate results
 SET citus.enable_cte_inlining TO false;
 
+-- prevent using locally executing the intermediate results
+SET citus.task_assignment_policy TO "round-robin";
+
 SELECT pg_backend_pid() as pid \gset
 
 CREATE TABLE users_table (user_id int, user_name text);

src/test/regress/sql/locally_execute_intermediate_results.sql

@@ -0,0 +1,515 @@
+CREATE SCHEMA locally_execute_intermediate_results;
+SET search_path TO locally_execute_intermediate_results;
+SET citus.log_intermediate_results TO TRUE;
+SET citus.log_local_commands TO TRUE;
+SET client_min_messages TO DEBUG1;
+
+SET citus.shard_count TO 4;
+SET citus.next_shard_id TO 1580000;
+SET citus.shard_replication_factor TO 1;
+SET citus.replication_model TO 'streaming';
+
+CREATE TABLE table_1 (key int, value text);
+SELECT create_distributed_table('table_1', 'key');
+
+CREATE TABLE table_2 (key int, value text);
+SELECT create_distributed_table('table_2', 'key');
+
+CREATE TABLE ref_table (key int, value text);
+SELECT create_reference_table('ref_table');
+
+-- load some data
+INSERT INTO table_1    VALUES (1, '1'), (2, '2'), (3, '3'), (4, '4');
+INSERT INTO table_2    VALUES                     (3, '3'), (4, '4'), (5, '5'), (6, '6');
+INSERT INTO ref_table  VALUES (1, '1'), (2, '2'), (3, '3'), (4, '4'), (5, '5'), (6, '6');
+
+-- prevent PG 11 - PG 12 outputs to diverge
+-- and have a lot more CTEs recursively planned for the
+-- sake of increasing the test coverage
+SET citus.enable_cte_inlining TO false;
+
+-- the query cannot be executed locally, but still because of
+-- HAVING the intermediate result is written to local file as well
+WITH cte_1 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+
+-- subquery in the WHERE part of the query can be executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+table_2
+WHERE
+key > (SELECT key FROM cte_2 ORDER BY 1 LIMIT 1)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+
+-- subquery in the WHERE part of the query should not be executed locally
+-- because it can be pushed down with the jointree
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(key) FROM table_2)
+SELECT
+count(*)
+FROM
+table_2
+WHERE
+key > (SELECT max FROM cte_2)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+
+-- now all the intermediate results are safe to be in local files
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(key) FROM table_2),
+cte_3 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+cte_3
+WHERE
+key > (SELECT max FROM cte_2)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+
+-- multiple CTEs are joined inside HAVING, so written to file
+-- locally, but nothing executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1 JOIN cte_2 USING (max));
+
+
+-- multiple CTEs are joined inside HAVING, so written to file
+-- locally, also the join tree contains only another CTE, so should be
+-- executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(value) FROM table_1),
+cte_3 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+cte_3
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1 JOIN cte_2 USING (max));
+
+-- now, the CTE is going to be written locally,
+-- plus that is going to be read locally because
+-- of the aggragate over the cte in HAVING
+WITH cte_1 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max(max) FROM cte_1);
+
+
+-- two ctes are going to be written locally and executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT * FROM table_1)
+SELECT
+count(*)
+FROM
+cte_2
+GROUP BY key
+HAVING max(value) < (SELECT max(max) FROM cte_1);
+
+-- this time the same CTE is both joined with a distributed
+-- table and used in HAVING
+-- TODO: fixed by #3396
+WITH a AS (SELECT * FROM table_1)
+SELECT count(*),
+key
+FROM a JOIN table_2 USING (key)
+GROUP BY key
+HAVING (max(table_2.value) > (SELECT value FROM a));
+
+-- this time the same CTE is both joined with a distributed
+-- table and used in HAVING -- but used in another subquery/aggregate
+-- so one more level of recursive planning
+WITH a AS (SELECT * FROM table_1)
+SELECT count(*),
+key
+FROM a JOIN table_2 USING (key)
+GROUP BY key
+HAVING (max(table_2.value) = (SELECT max(value) FROM a));
+
+-- same query as the above, without the aggragate
+WITH a AS (SELECT max(key) as key, max(value) as value FROM ref_table)
+SELECT count(*),
+key
+FROM a JOIN ref_table USING (key)
+GROUP BY key
+HAVING (max(ref_table.value) <= (SELECT value FROM a));
+
+
+-- some edge cases around CTEs used inside other CTEs
+
+-- everything can be executed locally
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) FROM cte_2)
+SELECT * FROM cte_3;
+
+-- the join between cte_3 and table_2 has to happen remotely
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN table_2 USING (key) WHERE table_2.key = 1;
+
+-- the join between cte_3 and table_2 has to happen remotely
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN ref_table USING (key);
+
+
+\c - - - :worker_1_port
+
+-- now use the same queries on a worker
+SET search_path TO locally_execute_intermediate_results;
+SET citus.log_intermediate_results TO TRUE;
+SET citus.log_local_commands TO TRUE;
+SET client_min_messages TO DEBUG1;
+
+-- prevent PG 11 - PG 12 outputs to diverge
+-- and have a lot more CTEs recursively planned for the
+-- sake of increasing the test coverage
+SET citus.enable_cte_inlining TO false;
+
+-- the query cannot be executed locally, but still because of
+-- HAVING the intermediate result is written to local file as well
+WITH cte_1 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+
+-- On non-mx case the subquery in the WHERE part of the query can be executed locally
+-- however, on Citus MX we have this limitation where the query cannot be executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+table_2
+WHERE
+key > (SELECT key FROM cte_2 ORDER BY 1 LIMIT 1)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+
+-- subquery in the WHERE part of the query should not be executed locally
+-- because it can be pushed down with the jointree
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(key) FROM table_2)
+SELECT
+count(*)
+FROM
+table_2
+WHERE
+key > (SELECT max FROM cte_2)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+
+-- although all the intermediate results are safe to be in local files
+-- we currently do not support it on Citus MX
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(key) FROM table_2),
+cte_3 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+cte_3
+WHERE
+key > (SELECT max FROM cte_2)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+
+-- multiple CTEs are joined inside HAVING, so written to file
+-- locally, but nothing executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1 JOIN cte_2 USING (max));
+
+
+-- multiple CTEs are joined inside HAVING, so written to file
+-- locally, also the join tree contains only another CTE, so should be
+-- executed locally, but not on an Citus MX worker
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(value) FROM table_1),
+cte_3 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+cte_3
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1 JOIN cte_2 USING (max));
+
+-- now, the CTE is going to be written locally,
+-- plus that could have been read locally on the coordinator
+-- because of the aggragate over the cte in HAVING
+-- but not on Citus MX
+WITH cte_1 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max(max) FROM cte_1);
+
+
+-- two could have been written locally and executed locally
+-- on the coordinator, but not on the workers
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT * FROM table_1)
+SELECT
+count(*)
+FROM
+cte_2
+GROUP BY key
+HAVING max(value) < (SELECT max(max) FROM cte_1);
+
+-- this time the same CTE is both joined with a distributed
+-- table and used in HAVING
+-- TODO: fixed by #3396
+WITH a AS (SELECT * FROM table_1)
+SELECT count(*),
+key
+FROM a JOIN table_2 USING (key)
+GROUP BY key
+HAVING (max(table_2.value) > (SELECT value FROM a));
+
+-- this time the same CTE is both joined with a distributed
+-- table and used in HAVING -- but used in another subquery/aggregate
+-- so one more level of recursive planning
+WITH a AS (SELECT * FROM table_1)
+SELECT count(*),
+key
+FROM a JOIN table_2 USING (key)
+GROUP BY key
+HAVING (max(table_2.value) = (SELECT max(value) FROM a));
+
+-- same query as the above, without the aggragate
+WITH a AS (SELECT max(key) as key, max(value) as value FROM ref_table)
+SELECT count(*),
+key
+FROM a JOIN ref_table USING (key)
+GROUP BY key
+HAVING (max(ref_table.value) <= (SELECT value FROM a));
+
+
+-- some edge cases around CTEs used inside other CTEs
+
+-- everything could be executed locally on the coordinator,
+-- but not on the worker
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) FROM cte_2)
+SELECT * FROM cte_3;
+
+-- the join between cte_3 and table_2 has to could have happened
+-- locally since the key = 1 resides on this node
+-- but because of the current implementation limitations we can't
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN table_2 USING (key) WHERE table_2.key = 1;
+
+-- the join between cte_3 and table_2 has to cannot happen
+-- locally because the key = 2 resides on a remote node
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN table_2 USING (key) WHERE table_2.key = 2;
+
+-- the join between cte_3 and ref can could have happened locally
+-- but because of the current implementation limitations we can't
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN ref_table USING (key);
+
+
+-- finally, use round-robin policy on the workers with same set of queries
+set citus.task_assignment_policy TO "round-robin" ;
+-- the query cannot be executed locally, but still because of
+-- HAVING the intermediate result is written to local file as well
+WITH cte_1 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+
+-- On non-mx case the subquery in the WHERE part of the query can be executed locally
+-- however, on Citus MX we have this limitation where the query cannot be executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+table_2
+WHERE
+key > (SELECT key FROM cte_2 ORDER BY 1 LIMIT 1)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+
+-- subquery in the WHERE part of the query should not be executed locally
+-- because it can be pushed down with the jointree
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(key) FROM table_2)
+SELECT
+count(*)
+FROM
+table_2
+WHERE
+key > (SELECT max FROM cte_2)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+
+-- although all the intermediate results are safe to be in local files
+-- we currently do not support it on Citus MX
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(key) FROM table_2),
+cte_3 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+cte_3
+WHERE
+key > (SELECT max FROM cte_2)
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1);
+
+-- multiple CTEs are joined inside HAVING, so written to file
+-- locally, but nothing executed locally
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1 JOIN cte_2 USING (max));
+
+
+-- multiple CTEs are joined inside HAVING, so written to file
+-- locally, also the join tree contains only another CTE, so should be
+-- executed locally, but not on an Citus MX worker
+-- TODO: fixed by #3396
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT max(value) FROM table_1),
+cte_3 AS (SELECT * FROM table_2)
+SELECT
+count(*)
+FROM
+cte_3
+GROUP BY key
+HAVING max(value) > (SELECT max FROM cte_1 JOIN cte_2 USING (max));
+
+-- now, the CTE is going to be written locally,
+-- plus that could have been read locally on the coordinator
+-- because of the aggragate over the cte in HAVING
+-- but not on Citus MX
+WITH cte_1 AS (SELECT max(value) FROM table_1)
+SELECT
+count(*)
+FROM
+table_2
+GROUP BY key
+HAVING max(value) > (SELECT max(max) FROM cte_1);
+
+
+-- two could have been written locally and executed locally
+-- on the coordinator, but not on the workers
+WITH cte_1 AS (SELECT max(value) FROM table_1),
+cte_2 AS (SELECT * FROM table_1)
+SELECT
+count(*)
+FROM
+cte_2
+GROUP BY key
+HAVING max(value) < (SELECT max(max) FROM cte_1);
+
+-- this time the same CTE is both joined with a distributed
+-- table and used in HAVING
+-- TODO: fixed by #3396
+WITH a AS (SELECT * FROM table_1)
+SELECT count(*),
+key
+FROM a JOIN table_2 USING (key)
+GROUP BY key
+HAVING (max(table_2.value) > (SELECT value FROM a));
+
+-- this time the same CTE is both joined with a distributed
+-- table and used in HAVING -- but used in another subquery/aggregate
+-- so one more level of recursive planning
+WITH a AS (SELECT * FROM table_1)
+SELECT count(*),
+key
+FROM a JOIN table_2 USING (key)
+GROUP BY key
+HAVING (max(table_2.value) = (SELECT max(value) FROM a));
+
+-- same query as the above, without the aggragate
+WITH a AS (SELECT max(key) as key, max(value) as value FROM ref_table)
+SELECT count(*),
+key
+FROM a JOIN ref_table USING (key)
+GROUP BY key
+HAVING (max(ref_table.value) <= (SELECT value FROM a));
+
+
+-- some edge cases around CTEs used inside other CTEs
+
+-- everything could be executed locally on the coordinator,
+-- but not on the worker
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) FROM cte_2)
+SELECT * FROM cte_3;
+
+-- the join between cte_3 and table_2 has to could have happened
+-- locally since the key = 1 resides on this node
+-- but because of the current implementation limitations we can't
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN table_2 USING (key) WHERE table_2.key = 1;
+
+-- the join between cte_3 and table_2 has to cannot happen
+-- locally because the key = 2 resides on a remote node
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN table_2 USING (key) WHERE table_2.key = 2;
+
+-- the join between cte_3 and ref can could have happened locally
+-- but because of the current implementation limitations we can't
+WITH cte_1 as (SELECT * FROM table_1),
+cte_2 AS (SELECT * FROM cte_1),
+cte_3 AS (SELECT max(key) as key FROM cte_2)
+SELECT * FROM cte_3 JOIN ref_table USING (key);
+
+
+\c - - - :master_port
+
+SET client_min_messages TO ERROR;
+DROP SCHEMA locally_execute_intermediate_results CASCADE;

src/test/regress/sql/subquery_complex_target_list.sql

@@ -7,6 +7,10 @@ SET search_path TO subquery_complex, public;
 
 SET client_min_messages TO DEBUG1;
 
+-- the logs are enabled and it sometimes
+-- lead to flaky outputs when jit enabled
+SET jit_above_cost TO -1;
+
 -- COUNT DISTINCT at the top level query
 SELECT
   event_type, count(distinct value_2)