Convert some hard coded errors to deferred errors in router planner

src/backend/distributed/executor/citus_custom_scan.c

@@ -546,7 +546,8 @@ RegenerateTaskForFasthPathQuery(Job *workerJob)
 
 	GenerateSingleShardRouterTaskList(workerJob,
 									  relationShardList,
-									  placementList, shardId);
+									  placementList,
+									  shardId);
 }
 
 

src/backend/distributed/planner/multi_physical_planner.c

@@ -171,7 +171,8 @@ static Task * QueryPushdownTaskCreate(Query *originalQuery, int shardIndex,
 									  RelationRestrictionContext *restrictionContext,
 									  uint32 taskId,
 									  TaskType taskType,
-									  bool modifyRequiresCoordinatorEvaluation);
+									  bool modifyRequiresCoordinatorEvaluation,
+									  DeferredErrorMessage **planningError);
 static bool ShardIntervalsEqual(FmgrInfo *comparisonFunction,
 								Oid collation,
 								ShardInterval *firstInterval,
@@ -2105,11 +2106,16 @@ BuildJobTreeTaskList(Job *jobTree, PlannerRestrictionContext *plannerRestriction
 													relationRestrictionContext,
 													&isMultiShardQuery, NULL);
 
+			DeferredErrorMessage *deferredErrorMessage = NULL;
 			sqlTaskList = QueryPushdownSqlTaskList(job->jobQuery, job->jobId,
 												   plannerRestrictionContext->
 												   relationRestrictionContext,
 												   prunedRelationShardList, READ_TASK,
-												   false);
+												   false,
+												   &deferredErrorMessage);
+			if (deferredErrorMessage != NULL) {
+				RaiseDeferredErrorInternal(deferredErrorMessage, ERROR);
+			}									   
 		}
 		else
 		{
@@ -2187,7 +2193,8 @@ List *
 QueryPushdownSqlTaskList(Query *query, uint64 jobId,
 						 RelationRestrictionContext *relationRestrictionContext,
 						 List *prunedRelationShardList, TaskType taskType, bool
-						 modifyRequiresCoordinatorEvaluation)
+						 modifyRequiresCoordinatorEvaluation,
+						 DeferredErrorMessage **planningError)
 {
 	List *sqlTaskList = NIL;
 	ListCell *restrictionCell = NULL;
@@ -2201,8 +2208,11 @@ QueryPushdownSqlTaskList(Query *query, uint64 jobId,
 
 	if (list_length(relationRestrictionContext->relationRestrictionList) == 0)
 	{
-		ereport(ERROR, (errmsg("cannot handle complex subqueries when the "
+		*planningError = DeferredError(ERRCODE_FEATURE_NOT_SUPPORTED,
-							   "router executor is disabled")));
+						"cannot handle complex subqueries when the "
+						"router executor is disabled",
+						NULL, NULL);
+		return NIL;				
 	}
 
 	/* defaults to be used if this is a reference table-only query */
@@ -2227,8 +2237,11 @@ QueryPushdownSqlTaskList(Query *query, uint64 jobId,
 		/* we expect distributed tables to have the same shard count */
 		if (shardCount > 0 && shardCount != cacheEntry->shardIntervalArrayLength)
 		{
-			ereport(ERROR, (errmsg("shard counts of co-located tables do not "
+			*planningError = DeferredError(ERRCODE_FEATURE_NOT_SUPPORTED,
-								   "match")));
+				"shard counts of co-located tables do not "
+				"match",
+				NULL, NULL);
+			return NIL;
 		}
 
 		if (taskRequiredForShardIndex == NULL)
@@ -2291,7 +2304,11 @@ QueryPushdownSqlTaskList(Query *query, uint64 jobId,
 													 relationRestrictionContext,
 													 taskIdIndex,
 													 taskType,
-													 modifyRequiresCoordinatorEvaluation);
+													 modifyRequiresCoordinatorEvaluation,
+													 planningError);
+		if (*planningError != NULL) {
+			return NIL;
+		}											 
 		subqueryTask->jobId = jobId;
 		sqlTaskList = lappend(sqlTaskList, subqueryTask);
 
@@ -2467,7 +2484,8 @@ ErrorIfUnsupportedShardDistribution(Query *query)
 static Task *
 QueryPushdownTaskCreate(Query *originalQuery, int shardIndex,
 						RelationRestrictionContext *restrictionContext, uint32 taskId,
-						TaskType taskType, bool modifyRequiresCoordinatorEvaluation)
+						TaskType taskType, bool modifyRequiresCoordinatorEvaluation,
+						DeferredErrorMessage **planningError)
 {
 	Query *taskQuery = copyObject(originalQuery);
 
@@ -2546,8 +2564,12 @@ QueryPushdownTaskCreate(Query *originalQuery, int shardIndex,
 	List *taskPlacementList = PlacementsForWorkersContainingAllShards(taskShardList);
 	if (list_length(taskPlacementList) == 0)
 	{
-		ereport(ERROR, (errmsg("cannot find a worker that has active placements for all "
+		*planningError = DeferredError(ERRCODE_FEATURE_NOT_SUPPORTED,
-							   "shards in the query")));
+				"cannot find a worker that has active placements for all "
+				"shards in the query",
+				NULL, NULL);
+
+		return NULL;					   
 	}
 
 	/*

src/backend/distributed/planner/multi_router_planner.c

@@ -1781,7 +1781,11 @@ RouterJob(Query *originalQuery, PlannerRestrictionContext *plannerRestrictionCon
 												 relationRestrictionContext,
 												 prunedShardIntervalListList,
 												 MODIFY_TASK,
-												 requiresCoordinatorEvaluation);
+												 requiresCoordinatorEvaluation,
+												 planningError);
+		if (*planningError) {
+			return NULL;
+		}										 
 	}
 	else
 	{
@@ -1806,14 +1810,12 @@ GenerateSingleShardRouterTaskList(Job *job, List *relationShardList,
 {
 	Query *originalQuery = job->jobQuery;
 
-
 	if (originalQuery->commandType == CMD_SELECT)
 	{
 		job->taskList = SingleShardTaskList(originalQuery, job->jobId,
 											relationShardList, placementList,
 											shardId,
 											job->parametersInJobQueryResolved);
-
 		/*
 		 * Queries to reference tables, or distributed tables with multiple replica's have
 		 * their task placements reordered according to the configured

src/include/distributed/multi_physical_planner.h

@@ -576,7 +576,8 @@ extern List * QueryPushdownSqlTaskList(Query *query, uint64 jobId,
 									   RelationRestrictionContext *
 									   relationRestrictionContext,
 									   List *prunedRelationShardList, TaskType taskType,
-									   bool modifyRequiresCoordinatorEvaluation);
+									   bool modifyRequiresCoordinatorEvaluation,
+									   DeferredErrorMessage **planningError);
 
 /* function declarations for managing jobs */
 extern uint64 UniqueJobId(void);

src/include/distributed/multi_router_planner.h

@@ -84,7 +84,8 @@ extern List * TargetShardIntervalForFastPathQuery(Query *query,
 												  Const **outGoingPartitionValueConst);
 extern void GenerateSingleShardRouterTaskList(Job *job,
 																List *relationShardList,
-											  List *placementList, uint64 shardId);
+																List *placementList,
+																uint64 shardId);
 extern bool IsRouterPlannable(Query *query,
 							  PlannerRestrictionContext *plannerRestrictionContext);