diff --git a/src/backend/distributed/commands/utility_hook.c b/src/backend/distributed/commands/utility_hook.c
index f6911eb70..585456669 100644
--- a/src/backend/distributed/commands/utility_hook.c
+++ b/src/backend/distributed/commands/utility_hook.c
@@ -253,6 +253,31 @@ multi_ProcessUtility(PlannedStmt *pstmt,
 	}
 #endif
 
+	if (IsA(parsetree, DoStmt))
+	{
+		/*
+		 * All statements in a DO block are executed in a single transaciton,
+		 * so we need to keep track of whether we are inside a DO block.
+		 */
+		DoBlockLevel += 1;
+
+		PG_TRY();
+		{
+			standard_ProcessUtility(pstmt, queryString, context,
+									params, queryEnv, dest, completionTag);
+
+			DoBlockLevel -= 1;
+		}
+		PG_CATCH();
+		{
+			DoBlockLevel -= 1;
+			PG_RE_THROW();
+		}
+		PG_END_TRY();
+
+		return;
+	}
+
 	/* process SET LOCAL stmts of whitelisted GUCs in multi-stmt xacts */
 	if (IsA(parsetree, VariableSetStmt))
 	{
diff --git a/src/backend/distributed/executor/multi_router_executor.c b/src/backend/distributed/executor/multi_router_executor.c
index 460d399c1..a7d5c8215 100644
--- a/src/backend/distributed/executor/multi_router_executor.c
+++ b/src/backend/distributed/executor/multi_router_executor.c
@@ -87,6 +87,9 @@ bool EnableDeadlockPrevention = true;
 /* number of nested stored procedure call levels we are currently in */
 int StoredProcedureLevel = 0;
 
+/* number of nested DO block levels we are currently in */
+int DoBlockLevel = 0;
+
 /* sort the returning to get consistent outputs */
 bool SortReturning = false;
 
diff --git a/src/backend/distributed/planner/distributed_planner.c b/src/backend/distributed/planner/distributed_planner.c
index c5a8af5f0..10703055a 100644
--- a/src/backend/distributed/planner/distributed_planner.c
+++ b/src/backend/distributed/planner/distributed_planner.c
@@ -18,6 +18,7 @@
 #include "catalog/pg_type.h"
 #include "distributed/citus_nodefuncs.h"
 #include "distributed/citus_nodes.h"
+#include "distributed/function_call_delegation.h"
 #include "distributed/insert_select_planner.h"
 #include "distributed/intermediate_results.h"
 #include "distributed/metadata_cache.h"
@@ -192,6 +193,14 @@ distributed_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
 			AdjustPartitioningForDistributedPlanning(rangeTableList,
 													 setPartitionedTablesInherited);
 		}
+		else
+		{
+			DistributedPlan *delegatePlan = TryToDelegateFunctionCall(parse);
+			if (delegatePlan != NULL)
+			{
+				result = FinalizePlan(result, delegatePlan);
+			}
+		}
 	}
 	PG_CATCH();
 	{
diff --git a/src/backend/distributed/planner/function_call_delegation.c b/src/backend/distributed/planner/function_call_delegation.c
new file mode 100644
index 000000000..b9bdbb253
--- /dev/null
+++ b/src/backend/distributed/planner/function_call_delegation.c
@@ -0,0 +1,287 @@
+/*-------------------------------------------------------------------------
+ *
+ * function_call_delegation.c
+ *    Planning logic for delegating a function call to a worker when the
+ *    function was distributed with a distribution argument and the worker
+ *    has metadata.
+ *
+ * Copyright (c), Citus Data, Inc.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "catalog/pg_proc.h"
+#include "catalog/pg_type.h"
+#include "commands/defrem.h"
+#include "distributed/citus_custom_scan.h"
+#include "distributed/citus_ruleutils.h"
+#include "distributed/colocation_utils.h"
+#include "distributed/commands.h"
+#include "distributed/commands/multi_copy.h"
+#include "distributed/connection_management.h"
+#include "distributed/function_call_delegation.h"
+#include "distributed/master_metadata_utility.h"
+#include "distributed/master_protocol.h"
+#include "distributed/metadata_cache.h"
+#include "distributed/multi_executor.h"
+#include "distributed/multi_physical_planner.h"
+#include "distributed/remote_commands.h"
+#include "distributed/shard_pruning.h"
+#include "distributed/version_compat.h"
+#include "distributed/worker_manager.h"
+#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
+#include "nodes/parsenodes.h"
+#include "nodes/primnodes.h"
+#include "optimizer/clauses.h"
+#include "parser/parse_coerce.h"
+#if PG_VERSION_NUM >= 120000
+#include "parser/parsetree.h"
+#endif
+#include "miscadmin.h"
+#include "tcop/dest.h"
+#include "utils/lsyscache.h"
+#include "utils/syscache.h"
+
+static bool contain_param_walker(Node *node, void *context);
+
+/*
+ * contain_param_walker scans node for Param nodes.
+ * returns whether any such nodes found.
+ */
+static bool
+contain_param_walker(Node *node, void *context)
+{
+	return IsA(node, Param);
+}
+
+
+/*
+ * TryToDelegateFunctionCall calls a function on the worker if possible.
+ * We only support delegating the SELECT func(...) form for distributed
+ * functions colocated by distributed tables, and not more complicated
+ * forms involving multiple function calls, FROM clauses, WHERE clauses,
+ * ... Those complex forms are handled in the coordinator.
+ */
+DistributedPlan *
+TryToDelegateFunctionCall(Query *query)
+{
+	FromExpr *joinTree = NULL;
+	List *targetList = NIL;
+	TargetEntry *targetEntry = NULL;
+	FuncExpr *funcExpr = NULL;
+	DistObjectCacheEntry *procedure = NULL;
+	Oid colocatedRelationId = InvalidOid;
+	Const *partitionValue = NULL;
+	Datum partitionValueDatum = 0;
+	ShardInterval *shardInterval = NULL;
+	List *placementList = NIL;
+	DistTableCacheEntry *distTable = NULL;
+	Var *partitionColumn = NULL;
+	ShardPlacement *placement = NULL;
+	WorkerNode *workerNode = NULL;
+	StringInfo queryString = NULL;
+	Task *task = NULL;
+	Job *job = NULL;
+	DistributedPlan *distributedPlan = NULL;
+	int32 groupId = 0;
+
+	if (!CitusHasBeenLoaded() || !CheckCitusVersion(DEBUG4))
+	{
+		/* Citus is not ready to determine whether function is distributed */
+		return NULL;
+	}
+
+	groupId = GetLocalGroupId();
+	if (groupId != 0 || groupId == GROUP_ID_UPGRADING)
+	{
+		/* do not delegate from workers, or while upgrading */
+		return NULL;
+	}
+
+	if (query == NULL)
+	{
+		/* no query (mostly here to be defensive) */
+		return NULL;
+	}
+
+	joinTree = query->jointree;
+	if (joinTree == NULL)
+	{
+		/* no join tree (mostly here to be defensive) */
+		return NULL;
+	}
+
+	if (joinTree->quals != NULL)
+	{
+		/* query has a WHERE section */
+		return NULL;
+	}
+
+	if (joinTree->fromlist != NIL)
+	{
+		/* query has a FROM section */
+#if PG_VERSION_NUM >= 120000
+
+		/* in pg12 empty FROMs are represented with an RTE_RESULT */
+		if (list_length(joinTree->fromlist) == 1)
+		{
+			RangeTblRef *reference = linitial(joinTree->fromlist);
+			RangeTblEntry *rtentry = rt_fetch(reference->rtindex, query->rtable);
+			if (rtentry->rtekind != RTE_RESULT)
+			{
+				return NULL;
+			}
+		}
+		else
+		{
+			return NULL;
+		}
+#else
+		return NULL;
+#endif
+	}
+
+	targetList = query->targetList;
+	if (list_length(query->targetList) != 1)
+	{
+		/* multiple target list items */
+		return NULL;
+	}
+
+	targetEntry = (TargetEntry *) linitial(targetList);
+	if (!IsA(targetEntry->expr, FuncExpr))
+	{
+		/* target list item is not a function call */
+		return NULL;
+	}
+
+	funcExpr = (FuncExpr *) targetEntry->expr;
+	procedure = LookupDistObjectCacheEntry(ProcedureRelationId, funcExpr->funcid, 0);
+	if (procedure == NULL)
+	{
+		/* not a distributed function call */
+		ereport(DEBUG4, (errmsg("function is not distributed")));
+		return NULL;
+	}
+
+	if (IsMultiStatementTransaction())
+	{
+		/* cannot delegate function calls in a multi-statement transaction */
+		ereport(DEBUG1, (errmsg("not pushing down function calls in "
+								"a multi-statement transaction")));
+		return NULL;
+	}
+
+	if (procedure->distributionArgIndex < 0 ||
+		procedure->distributionArgIndex >= list_length(funcExpr->args))
+	{
+		ereport(DEBUG1, (errmsg("function call does not have a distribution argument")));
+		return NULL;
+	}
+
+	if (contain_volatile_functions((Node *) funcExpr->args))
+	{
+		ereport(DEBUG1, (errmsg("arguments in a distributed function must "
+								"be constant expressions")));
+		return NULL;
+	}
+
+	if (expression_tree_walker((Node *) funcExpr->args, contain_param_walker, NULL))
+	{
+		ereport(DEBUG1, (errmsg("arguments in a distributed function must "
+								"not contain subqueries")));
+		return NULL;
+	}
+
+	colocatedRelationId = ColocatedTableId(procedure->colocationId);
+	if (colocatedRelationId == InvalidOid)
+	{
+		ereport(DEBUG1, (errmsg("function does not have co-located tables")));
+		return NULL;
+	}
+
+	distTable = DistributedTableCacheEntry(colocatedRelationId);
+	partitionColumn = distTable->partitionColumn;
+	if (partitionColumn == NULL)
+	{
+		/* This can happen if colocated with a reference table. Punt for now. */
+		ereport(DEBUG1, (errmsg(
+							 "cannnot push down function call for reference tables")));
+		return NULL;
+	}
+
+	partitionValue = (Const *) list_nth(funcExpr->args, procedure->distributionArgIndex);
+	if (!IsA(partitionValue, Const))
+	{
+		ereport(DEBUG1, (errmsg("distribution argument value must be a constant")));
+		return NULL;
+	}
+
+	partitionValueDatum = partitionValue->constvalue;
+
+	if (partitionValue->consttype != partitionColumn->vartype)
+	{
+		CopyCoercionData coercionData;
+
+		ConversionPathForTypes(partitionValue->consttype, partitionColumn->vartype,
+							   &coercionData);
+
+		partitionValueDatum = CoerceColumnValue(partitionValueDatum, &coercionData);
+	}
+
+	shardInterval = FindShardInterval(partitionValueDatum, distTable);
+	if (shardInterval == NULL)
+	{
+		ereport(DEBUG1, (errmsg("cannot push down call, failed to find shard interval")));
+		return NULL;
+	}
+
+	placementList = FinalizedShardPlacementList(shardInterval->shardId);
+	if (list_length(placementList) != 1)
+	{
+		/* punt on this for now */
+		ereport(DEBUG1, (errmsg(
+							 "cannot push down function call for replicated distributed tables")));
+		return NULL;
+	}
+
+	placement = (ShardPlacement *) linitial(placementList);
+	workerNode = FindWorkerNode(placement->nodeName, placement->nodePort);
+
+	if (workerNode == NULL || !workerNode->hasMetadata || !workerNode->metadataSynced)
+	{
+		ereport(DEBUG1, (errmsg("the worker node does not have metadata")));
+		return NULL;
+	}
+
+	ereport(DEBUG1, (errmsg("pushing down the function call")));
+
+	queryString = makeStringInfo();
+	pg_get_query_def(query, queryString);
+
+	task = CitusMakeNode(Task);
+	task->taskType = SQL_TASK;
+	task->queryString = queryString->data;
+	task->taskPlacementList = placementList;
+	task->anchorShardId = shardInterval->shardId;
+	task->replicationModel = distTable->replicationModel;
+
+	job = CitusMakeNode(Job);
+	job->jobId = UniqueJobId();
+	job->jobQuery = query;
+	job->taskList = list_make1(task);
+
+	distributedPlan = CitusMakeNode(DistributedPlan);
+	distributedPlan->workerJob = job;
+	distributedPlan->masterQuery = NULL;
+	distributedPlan->routerExecutable = true;
+	distributedPlan->hasReturning = false;
+
+	/* worker will take care of any necessary locking, treat query as read-only */
+	distributedPlan->modLevel = ROW_MODIFY_READONLY;
+
+	return distributedPlan;
+}
diff --git a/src/backend/distributed/transaction/transaction_management.c b/src/backend/distributed/transaction/transaction_management.c
index 9168b0cb7..ed0b94c03 100644
--- a/src/backend/distributed/transaction/transaction_management.c
+++ b/src/backend/distributed/transaction/transaction_management.c
@@ -638,6 +638,11 @@ IsMultiStatementTransaction(void)
 		/* in a BEGIN...END block */
 		return true;
 	}
+	else if (DoBlockLevel > 0)
+	{
+		/* in (a transaction within) a do block */
+		return true;
+	}
 	else if (StoredProcedureLevel > 0)
 	{
 		/* in (a transaction within) a stored procedure */
diff --git a/src/backend/distributed/utils/metadata_cache.c b/src/backend/distributed/utils/metadata_cache.c
index fa637c5e7..e455575d3 100644
--- a/src/backend/distributed/utils/metadata_cache.c
+++ b/src/backend/distributed/utils/metadata_cache.c
@@ -3143,18 +3143,22 @@ GetLocalGroupId(void)
 										  tupleDescriptor, &isNull);
 
 		groupId = DatumGetInt32(groupIdDatum);
+
+		/* set the local cache variable */
+		LocalGroupId = groupId;
 	}
 	else
 	{
-		elog(ERROR, "could not find any entries in pg_dist_local_group");
+		/*
+		 * Upgrade is happening. When upgrading postgres, pg_dist_local_group is
+		 * temporarily empty before citus_finish_pg_upgrade() finishes execution.
+		 */
+		groupId = GROUP_ID_UPGRADING;
 	}
 
 	systable_endscan(scanDescriptor);
 	heap_close(pgDistLocalGroupId, AccessShareLock);
 
-	/* set the local cache variable */
-	LocalGroupId = groupId;
-
 	return groupId;
 }
 
diff --git a/src/include/distributed/function_call_delegation.h b/src/include/distributed/function_call_delegation.h
new file mode 100644
index 000000000..830e5e9ea
--- /dev/null
+++ b/src/include/distributed/function_call_delegation.h
@@ -0,0 +1,19 @@
+/*
+ * function_call_delegation.h
+ *    Declarations for public functions and variables used to delegate
+ *    function calls to worker nodes.
+ *
+ * Copyright (c), Citus Data, Inc.
+ */
+
+#ifndef FUNCTION_CALL_DELEGATION_H
+#define FUNCTION_CALL_DELEGATION_H
+
+#include "postgres.h"
+#include "distributed/multi_physical_planner.h"
+
+
+DistributedPlan * TryToDelegateFunctionCall(Query *query);
+
+
+#endif /* FUNCTION_CALL_DELEGATION_H */
diff --git a/src/include/distributed/metadata_cache.h b/src/include/distributed/metadata_cache.h
index f63d26816..77280aebf 100644
--- a/src/include/distributed/metadata_cache.h
+++ b/src/include/distributed/metadata_cache.h
@@ -29,6 +29,14 @@ typedef enum
 } ReadFromSecondariesType;
 extern int ReadFromSecondaries;
 
+
+/*
+ * While upgrading pg_dist_local_group can be empty temporarily, in that
+ * case we use GROUP_ID_UPGRADING as the local group id to communicate
+ * this to other functions.
+ */
+#define GROUP_ID_UPGRADING -2
+
 /*
  * Representation of a table's metadata that is frequently used for
  * distributed execution. Cached.
diff --git a/src/include/distributed/transaction_management.h b/src/include/distributed/transaction_management.h
index 70365a9d6..51645dd17 100644
--- a/src/include/distributed/transaction_management.h
+++ b/src/include/distributed/transaction_management.h
@@ -91,6 +91,9 @@ extern dlist_head InProgressTransactions;
 /* number of nested stored procedure call levels we are currently in */
 extern int StoredProcedureLevel;
 
+/* number of nested DO block levels we are currently in */
+extern int DoBlockLevel;
+
 /* number of nested function call levels we are currently in */
 extern int FunctionCallLevel;
 
diff --git a/src/test/regress/expected/multi_mx_call.out b/src/test/regress/expected/multi_mx_call.out
index 36209baf4..55d07c4a2 100644
--- a/src/test/regress/expected/multi_mx_call.out
+++ b/src/test/regress/expected/multi_mx_call.out
@@ -1,4 +1,6 @@
 -- Test passing off CALL to mx workers
+create schema multi_mx_call;
+set search_path to multi_mx_call, public;
 -- Create worker-local tables to test procedure calls were routed
 set citus.shard_replication_factor to 2;
 set citus.replication_model to 'statement';
@@ -13,21 +15,6 @@ select create_distributed_table('mx_call_dist_table_replica', 'id');
 insert into mx_call_dist_table_replica values (9,1),(8,2),(7,3),(6,4),(5,5);
 set citus.shard_replication_factor to 1;
 set citus.replication_model to 'streaming';
-create schema multi_mx_call;
-set search_path to multi_mx_call, public;
---
--- Utility UDFs
---
--- 1. Marks the given procedure as colocated with the given table.
--- 2. Marks the argument index with which we route the procedure.
-CREATE PROCEDURE colocate_proc_with_table(procname text, tablerelid regclass, argument_index int)
-LANGUAGE plpgsql AS $$
-BEGIN
-    update citus.pg_dist_object
-    set distribution_argument_index = argument_index, colocationid = pg_dist_partition.colocationid
-    from pg_proc, pg_dist_partition
-    where proname = procname and oid = objid and pg_dist_partition.logicalrelid = tablerelid;
-END;$$;
 --
 -- Create tables and procedures we want to use in tests
 --
@@ -96,6 +83,19 @@ call multi_mx_call.mx_call_proc_custom_types('S', 'A');
  F | S
 (1 row)
 
+-- Same for unqualified names
+call mx_call_proc(2, 0);
+ y  
+----
+ 29
+(1 row)
+
+call mx_call_proc_custom_types('S', 'A');
+ x | y 
+---+---
+ F | S
+(1 row)
+
 -- Mark both procedures as distributed ...
 select create_distributed_function('mx_call_proc(int,int)');
  create_distributed_function 
@@ -114,10 +114,10 @@ select create_distributed_function('mx_call_proc_custom_types(mx_call_enum,mx_ca
 SET client_min_messages TO DEBUG1;
 call multi_mx_call.mx_call_proc(2, 0);
 DEBUG:  stored procedure does not have co-located tables
-DEBUG:  generating subplan 8_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+DEBUG:  generating subplan 10_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
 CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
 PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
-DEBUG:  Plan 8 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('8_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+DEBUG:  Plan 10 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('10_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
 CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
 PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
  y  
@@ -133,8 +133,18 @@ DEBUG:  stored procedure does not have co-located tables
 (1 row)
 
 -- Mark them as colocated with a table. Now we should route them to workers.
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 1);
-call multi_mx_call.colocate_proc_with_table('mx_call_proc_custom_types', 'mx_call_dist_table_enum'::regclass, 1);
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
+select colocate_proc_with_table('mx_call_proc_custom_types', 'mx_call_dist_table_enum'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
 call multi_mx_call.mx_call_proc(2, 0);
 DEBUG:  pushing down the procedure
  y  
@@ -149,14 +159,28 @@ DEBUG:  pushing down the procedure
  S | S
 (1 row)
 
+call mx_call_proc(2, 0);
+DEBUG:  pushing down the procedure
+ y  
+----
+ 28
+(1 row)
+
+call mx_call_proc_custom_types('S', 'A');
+DEBUG:  pushing down the procedure
+ x | y 
+---+---
+ S | S
+(1 row)
+
 -- We don't allow distributing calls inside transactions
 begin;
 call multi_mx_call.mx_call_proc(2, 0);
 DEBUG:  cannot push down CALL in multi-statement transaction
-DEBUG:  generating subplan 10_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+DEBUG:  generating subplan 12_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
 CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
 PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
-DEBUG:  Plan 10 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('10_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+DEBUG:  Plan 12 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('12_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
 CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
 PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
  y  
@@ -179,21 +203,12 @@ DEBUG:  stored procedure does not have co-located tables
 
 -- Make sure we do bounds checking on distributed argument index
 -- This also tests that we have cache invalidation for pg_dist_object updates
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, -1);
-call multi_mx_call.mx_call_proc(2, 0);
-DEBUG:  cannot push down invalid distribution_argument_index
-DEBUG:  generating subplan 12_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
-CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
-PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
-DEBUG:  Plan 12 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('12_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
-CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
-PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
- y  
-----
- 29
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, -1);
+ colocate_proc_with_table 
+--------------------------
+ 
 (1 row)
 
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 2);
 call multi_mx_call.mx_call_proc(2, 0);
 DEBUG:  cannot push down invalid distribution_argument_index
 DEBUG:  generating subplan 14_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
@@ -207,10 +222,14 @@ PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
  29
 (1 row)
 
--- We don't currently support colocating with reference tables
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_ref'::regclass, 1);
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 2);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
 call multi_mx_call.mx_call_proc(2, 0);
-DEBUG:  cannot push down CALL for reference tables
+DEBUG:  cannot push down invalid distribution_argument_index
 DEBUG:  generating subplan 17_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
 CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
 PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
@@ -222,10 +241,15 @@ PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
  29
 (1 row)
 
--- We don't currently support colocating with replicated tables
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_replica'::regclass, 1);
+-- We don't currently support colocating with reference tables
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_ref'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
 call multi_mx_call.mx_call_proc(2, 0);
-DEBUG:  cannot push down CALL for replicated distributed tables
+DEBUG:  cannot push down CALL for reference tables
 DEBUG:  generating subplan 19_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
 CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
 PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
@@ -237,20 +261,45 @@ PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
  29
 (1 row)
 
+-- We don't currently support colocating with replicated tables
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_replica'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
+call multi_mx_call.mx_call_proc(2, 0);
+DEBUG:  cannot push down CALL for replicated distributed tables
+DEBUG:  generating subplan 21_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
+DEBUG:  Plan 21 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('21_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
+ y  
+----
+ 29
+(1 row)
+
 SET client_min_messages TO NOTICE;
 drop table mx_call_dist_table_replica;
 SET client_min_messages TO DEBUG1;
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 1);
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
 -- Test that we handle transactional constructs correctly inside a procedure
 -- that is routed to the workers.
 CREATE PROCEDURE mx_call_proc_tx(x int) LANGUAGE plpgsql AS $$
 BEGIN
-    INSERT INTO mx_call_dist_table_1 VALUES (x, -1), (x+1, 4);
+    INSERT INTO multi_mx_call.mx_call_dist_table_1 VALUES (x, -1), (x+1, 4);
     COMMIT;
-    UPDATE mx_call_dist_table_1 SET val = val+1 WHERE id >= x;
+    UPDATE multi_mx_call.mx_call_dist_table_1 SET val = val+1 WHERE id >= x;
     ROLLBACK;
     -- Now do the final update!
-    UPDATE mx_call_dist_table_1 SET val = val-1 WHERE id >= x;
+    UPDATE multi_mx_call.mx_call_dist_table_1 SET val = val-1 WHERE id >= x;
 END;$$;
 -- before distribution ...
 CALL multi_mx_call.mx_call_proc_tx(10);
@@ -265,9 +314,6 @@ DETAIL:  A distributed function is created. To make sure subsequent commands see
 
 CALL multi_mx_call.mx_call_proc_tx(20);
 DEBUG:  pushing down the procedure
-ERROR:  relation "mx_call_dist_table_1" does not exist
-CONTEXT:  while executing command on localhost:57637
-PL/pgSQL function multi_mx_call.mx_call_proc_tx(integer) line 3 at SQL statement
 SELECT id, val FROM mx_call_dist_table_1 ORDER BY id, val;
  id | val 
 ----+-----
@@ -278,7 +324,9 @@ SELECT id, val FROM mx_call_dist_table_1 ORDER BY id, val;
   9 |   2
  10 |  -2
  11 |   3
-(7 rows)
+ 20 |  -2
+ 21 |   3
+(9 rows)
 
 -- Test that we properly propagate errors raised from procedures.
 CREATE PROCEDURE mx_call_proc_raise(x int) LANGUAGE plpgsql AS $$
@@ -316,10 +364,10 @@ select stop_metadata_sync_to_node('localhost', :worker_2_port);
 
 call multi_mx_call.mx_call_proc(2, 0);
 DEBUG:  there is no worker node with metadata
-DEBUG:  generating subplan 25_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+DEBUG:  generating subplan 27_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
 CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
 PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
-DEBUG:  Plan 25 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('25_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+DEBUG:  Plan 27 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('27_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
 CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
 PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
  y  
@@ -340,6 +388,11 @@ select start_metadata_sync_to_node('localhost', :worker_2_port);
  
 (1 row)
 
+-- stop_metadata_sync_to_node()/start_metadata_sync_to_node() might make
+-- worker backend caches inconsistent. Reconnect to coordinator to use
+-- new worker connections, hence new backends.
+\c - - - :master_port
+SET search_path to multi_mx_call, public;
 SET client_min_messages TO DEBUG1;
 --
 -- Test non-const parameter values
@@ -357,10 +410,10 @@ DETAIL:  A distributed function is created. To make sure subsequent commands see
 -- non-const distribution parameters cannot be pushed down
 call multi_mx_call.mx_call_proc(2, mx_call_add(3, 4));
 DEBUG:  distribution argument value must be a constant
-DEBUG:  generating subplan 27_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+DEBUG:  generating subplan 1_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
 CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
 PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
-DEBUG:  Plan 27 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('27_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+DEBUG:  Plan 1 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('1_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
 CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
 PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
  y  
@@ -379,10 +432,10 @@ DEBUG:  pushing down the procedure
 -- volatile parameter cannot be pushed down
 call multi_mx_call.mx_call_proc(floor(random())::int, 2);
 DEBUG:  arguments in a distributed stored procedure must be constant expressions
-DEBUG:  generating subplan 29_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+DEBUG:  generating subplan 3_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_call.mx_call_dist_table_1 t1 JOIN multi_mx_call.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
 CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
 PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
-DEBUG:  Plan 29 query after replacing subqueries and CTEs: SELECT (1 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('29_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+DEBUG:  Plan 3 query after replacing subqueries and CTEs: SELECT (1 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('3_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
 CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_call.mx_call_dist_table_1 t1 join multi_mx_call.mx_call_dist_table_2 t2 on t1.id = t2.id)"
 PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
  y  
@@ -393,4 +446,4 @@ PL/pgSQL function mx_call_proc(integer,integer) line 8 at assignment
 reset client_min_messages;
 \set VERBOSITY terse
 drop schema multi_mx_call cascade;
-NOTICE:  drop cascades to 10 other objects
+NOTICE:  drop cascades to 9 other objects
diff --git a/src/test/regress/expected/multi_mx_call_0.out b/src/test/regress/expected/multi_mx_call_0.out
index a5dac9c72..f16f2d551 100644
--- a/src/test/regress/expected/multi_mx_call_0.out
+++ b/src/test/regress/expected/multi_mx_call_0.out
@@ -1,4 +1,6 @@
 -- Test passing off CALL to mx workers
+create schema multi_mx_call;
+set search_path to multi_mx_call, public;
 -- Create worker-local tables to test procedure calls were routed
 set citus.shard_replication_factor to 2;
 set citus.replication_model to 'statement';
@@ -13,24 +15,6 @@ select create_distributed_table('mx_call_dist_table_replica', 'id');
 insert into mx_call_dist_table_replica values (9,1),(8,2),(7,3),(6,4),(5,5);
 set citus.shard_replication_factor to 1;
 set citus.replication_model to 'streaming';
-create schema multi_mx_call;
-set search_path to multi_mx_call, public;
---
--- Utility UDFs
---
--- 1. Marks the given procedure as colocated with the given table.
--- 2. Marks the argument index with which we route the procedure.
-CREATE PROCEDURE colocate_proc_with_table(procname text, tablerelid regclass, argument_index int)
-LANGUAGE plpgsql AS $$
-BEGIN
-    update citus.pg_dist_object
-    set distribution_argument_index = argument_index, colocationid = pg_dist_partition.colocationid
-    from pg_proc, pg_dist_partition
-    where proname = procname and oid = objid and pg_dist_partition.logicalrelid = tablerelid;
-END;$$;
-ERROR:  syntax error at or near "PROCEDURE"
-LINE 1: CREATE PROCEDURE colocate_proc_with_table(procname text, tab...
-               ^
 --
 -- Create tables and procedures we want to use in tests
 --
@@ -101,6 +85,15 @@ call multi_mx_call.mx_call_proc_custom_types('S', 'A');
 ERROR:  syntax error at or near "call"
 LINE 1: call multi_mx_call.mx_call_proc_custom_types('S', 'A');
         ^
+-- Same for unqualified names
+call mx_call_proc(2, 0);
+ERROR:  syntax error at or near "call"
+LINE 1: call mx_call_proc(2, 0);
+        ^
+call mx_call_proc_custom_types('S', 'A');
+ERROR:  syntax error at or near "call"
+LINE 1: call mx_call_proc_custom_types('S', 'A');
+        ^
 -- Mark both procedures as distributed ...
 select create_distributed_function('mx_call_proc(int,int)');
 ERROR:  function "mx_call_proc(int,int)" does not exist
@@ -122,14 +115,18 @@ ERROR:  syntax error at or near "call"
 LINE 1: call multi_mx_call.mx_call_proc_custom_types('S', 'A');
         ^
 -- Mark them as colocated with a table. Now we should route them to workers.
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 1);
-ERROR:  syntax error at or near "call"
-LINE 1: call multi_mx_call.colocate_proc_with_table('mx_call_proc', ...
-        ^
-call multi_mx_call.colocate_proc_with_table('mx_call_proc_custom_types', 'mx_call_dist_table_enum'::regclass, 1);
-ERROR:  syntax error at or near "call"
-LINE 1: call multi_mx_call.colocate_proc_with_table('mx_call_proc_cu...
-        ^
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
+select colocate_proc_with_table('mx_call_proc_custom_types', 'mx_call_dist_table_enum'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
 call multi_mx_call.mx_call_proc(2, 0);
 ERROR:  syntax error at or near "call"
 LINE 1: call multi_mx_call.mx_call_proc(2, 0);
@@ -138,6 +135,14 @@ call multi_mx_call.mx_call_proc_custom_types('S', 'A');
 ERROR:  syntax error at or near "call"
 LINE 1: call multi_mx_call.mx_call_proc_custom_types('S', 'A');
         ^
+call mx_call_proc(2, 0);
+ERROR:  syntax error at or near "call"
+LINE 1: call mx_call_proc(2, 0);
+        ^
+call mx_call_proc_custom_types('S', 'A');
+ERROR:  syntax error at or near "call"
+LINE 1: call mx_call_proc_custom_types('S', 'A');
+        ^
 -- We don't allow distributing calls inside transactions
 begin;
 call multi_mx_call.mx_call_proc(2, 0);
@@ -156,36 +161,44 @@ LINE 1: call multi_mx_call.mx_call_proc_custom_types('S', 'A');
         ^
 -- Make sure we do bounds checking on distributed argument index
 -- This also tests that we have cache invalidation for pg_dist_object updates
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, -1);
-ERROR:  syntax error at or near "call"
-LINE 1: call multi_mx_call.colocate_proc_with_table('mx_call_proc', ...
-        ^
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, -1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
 call multi_mx_call.mx_call_proc(2, 0);
 ERROR:  syntax error at or near "call"
 LINE 1: call multi_mx_call.mx_call_proc(2, 0);
         ^
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 2);
-ERROR:  syntax error at or near "call"
-LINE 1: call multi_mx_call.colocate_proc_with_table('mx_call_proc', ...
-        ^
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 2);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
 call multi_mx_call.mx_call_proc(2, 0);
 ERROR:  syntax error at or near "call"
 LINE 1: call multi_mx_call.mx_call_proc(2, 0);
         ^
 -- We don't currently support colocating with reference tables
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_ref'::regclass, 1);
-ERROR:  syntax error at or near "call"
-LINE 1: call multi_mx_call.colocate_proc_with_table('mx_call_proc', ...
-        ^
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_ref'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
 call multi_mx_call.mx_call_proc(2, 0);
 ERROR:  syntax error at or near "call"
 LINE 1: call multi_mx_call.mx_call_proc(2, 0);
         ^
 -- We don't currently support colocating with replicated tables
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_replica'::regclass, 1);
-ERROR:  syntax error at or near "call"
-LINE 1: call multi_mx_call.colocate_proc_with_table('mx_call_proc', ...
-        ^
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_replica'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
 call multi_mx_call.mx_call_proc(2, 0);
 ERROR:  syntax error at or near "call"
 LINE 1: call multi_mx_call.mx_call_proc(2, 0);
@@ -193,20 +206,22 @@ LINE 1: call multi_mx_call.mx_call_proc(2, 0);
 SET client_min_messages TO NOTICE;
 drop table mx_call_dist_table_replica;
 SET client_min_messages TO DEBUG1;
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 1);
-ERROR:  syntax error at or near "call"
-LINE 1: call multi_mx_call.colocate_proc_with_table('mx_call_proc', ...
-        ^
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
 -- Test that we handle transactional constructs correctly inside a procedure
 -- that is routed to the workers.
 CREATE PROCEDURE mx_call_proc_tx(x int) LANGUAGE plpgsql AS $$
 BEGIN
-    INSERT INTO mx_call_dist_table_1 VALUES (x, -1), (x+1, 4);
+    INSERT INTO multi_mx_call.mx_call_dist_table_1 VALUES (x, -1), (x+1, 4);
     COMMIT;
-    UPDATE mx_call_dist_table_1 SET val = val+1 WHERE id >= x;
+    UPDATE multi_mx_call.mx_call_dist_table_1 SET val = val+1 WHERE id >= x;
     ROLLBACK;
     -- Now do the final update!
-    UPDATE mx_call_dist_table_1 SET val = val-1 WHERE id >= x;
+    UPDATE multi_mx_call.mx_call_dist_table_1 SET val = val-1 WHERE id >= x;
 END;$$;
 ERROR:  syntax error at or near "PROCEDURE"
 LINE 1: CREATE PROCEDURE mx_call_proc_tx(x int) LANGUAGE plpgsql AS ...
@@ -282,6 +297,11 @@ select start_metadata_sync_to_node('localhost', :worker_2_port);
  
 (1 row)
 
+-- stop_metadata_sync_to_node()/start_metadata_sync_to_node() might make
+-- worker backend caches inconsistent. Reconnect to coordinator to use
+-- new worker connections, hence new backends.
+\c - - - :master_port
+SET search_path to multi_mx_call, public;
 SET client_min_messages TO DEBUG1;
 --
 -- Test non-const parameter values
diff --git a/src/test/regress/expected/multi_mx_function_call_delegation.out b/src/test/regress/expected/multi_mx_function_call_delegation.out
new file mode 100644
index 000000000..5c54674c3
--- /dev/null
+++ b/src/test/regress/expected/multi_mx_function_call_delegation.out
@@ -0,0 +1,539 @@
+-- Test passing off function call to mx workers
+CREATE SCHEMA multi_mx_function_call_delegation;
+SET search_path TO multi_mx_function_call_delegation, public;
+SET citus.shard_replication_factor TO 2;
+SET citus.replication_model TO 'statement';
+-- This table requires specific settings, create before getting into things
+create table mx_call_dist_table_replica(id int, val int);
+select create_distributed_table('mx_call_dist_table_replica', 'id');
+ create_distributed_table 
+--------------------------
+ 
+(1 row)
+
+insert into mx_call_dist_table_replica values (9,1),(8,2),(7,3),(6,4),(5,5);
+SET citus.shard_replication_factor TO 1;
+SET citus.replication_model TO 'streaming';
+--
+-- Create tables and functions we want to use in tests
+--
+create table mx_call_dist_table_1(id int, val int);
+select create_distributed_table('mx_call_dist_table_1', 'id');
+ create_distributed_table 
+--------------------------
+ 
+(1 row)
+
+insert into mx_call_dist_table_1 values (3,1),(4,5),(9,2),(6,5),(3,5);
+create table mx_call_dist_table_2(id int, val int);
+select create_distributed_table('mx_call_dist_table_2', 'id');
+ create_distributed_table 
+--------------------------
+ 
+(1 row)
+
+insert into mx_call_dist_table_2 values (1,1),(1,2),(2,2),(3,3),(3,4);
+create table mx_call_dist_table_ref(id int, val int);
+select create_reference_table('mx_call_dist_table_ref');
+ create_reference_table 
+------------------------
+ 
+(1 row)
+
+insert into mx_call_dist_table_ref values (2,7),(1,8),(2,8),(1,8),(2,8);
+create type mx_call_enum as enum ('A', 'S', 'D', 'F');
+create table mx_call_dist_table_enum(id int, key mx_call_enum);
+select create_distributed_table('mx_call_dist_table_enum', 'key');
+ create_distributed_table 
+--------------------------
+ 
+(1 row)
+
+insert into mx_call_dist_table_enum values (1,'S'),(2,'A'),(3,'D'),(4,'F');
+CREATE FUNCTION squares(int) RETURNS SETOF RECORD
+    AS $$ SELECT i, i * i FROM generate_series(1, $1) i $$
+    LANGUAGE SQL;
+CREATE FUNCTION mx_call_func(x int, INOUT y int)
+LANGUAGE plpgsql AS $$
+BEGIN
+    -- groupid is 0 in coordinator and non-zero in workers, so by using it here
+    -- we make sure the function is being executed in the worker.
+    y := x + (select case groupid when 0 then 1 else 0 end from pg_dist_local_group);
+    -- we also make sure that we can run distributed queries in the functions
+    -- that are routed to the workers.
+    y := y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id);
+END;$$;
+-- create another function which verifies:
+-- 1. we work fine with multiple return columns
+-- 2. we work fine in combination with custom types
+CREATE FUNCTION mx_call_func_custom_types(INOUT x mx_call_enum, INOUT y mx_call_enum)
+LANGUAGE plpgsql AS $$
+BEGIN
+    y := x;
+    x := (select case groupid when 0 then 'F' else 'S' end from pg_dist_local_group);
+END;$$;
+-- Test that undistributed functions have no issue executing
+select multi_mx_function_call_delegation.mx_call_func(2, 0);
+ mx_call_func 
+--------------
+           29
+(1 row)
+
+select multi_mx_function_call_delegation.mx_call_func_custom_types('S', 'A');
+ mx_call_func_custom_types 
+---------------------------
+ (F,S)
+(1 row)
+
+select squares(4);
+ squares 
+---------
+ (1,1)
+ (2,4)
+ (3,9)
+ (4,16)
+(4 rows)
+
+-- Same for unqualified name
+select mx_call_func(2, 0);
+ mx_call_func 
+--------------
+           29
+(1 row)
+
+-- Mark both functions as distributed ...
+select create_distributed_function('mx_call_func(int,int)');
+ create_distributed_function 
+-----------------------------
+ 
+(1 row)
+
+select create_distributed_function('mx_call_func_custom_types(mx_call_enum,mx_call_enum)');
+ create_distributed_function 
+-----------------------------
+ 
+(1 row)
+
+select create_distributed_function('squares(int)');
+ create_distributed_function 
+-----------------------------
+ 
+(1 row)
+
+-- We still don't route them to the workers, because they aren't
+-- colocated with any distributed tables.
+SET client_min_messages TO DEBUG1;
+select mx_call_func(2, 0);
+DEBUG:  function does not have co-located tables
+DEBUG:  generating subplan 10_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_function_call_delegation.mx_call_dist_table_1 t1 JOIN multi_mx_function_call_delegation.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  Plan 10 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('10_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+ mx_call_func 
+--------------
+           29
+(1 row)
+
+select mx_call_func_custom_types('S', 'A');
+DEBUG:  function does not have co-located tables
+ mx_call_func_custom_types 
+---------------------------
+ (F,S)
+(1 row)
+
+-- Mark them as colocated with a table. Now we should route them to workers.
+select colocate_proc_with_table('mx_call_func', 'mx_call_dist_table_1'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
+select colocate_proc_with_table('mx_call_func_custom_types', 'mx_call_dist_table_enum'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
+select colocate_proc_with_table('squares', 'mx_call_dist_table_2'::regclass, 0);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
+select mx_call_func(2, 0);
+DEBUG:  pushing down the function call
+ mx_call_func 
+--------------
+           28
+(1 row)
+
+select mx_call_func_custom_types('S', 'A');
+DEBUG:  pushing down the function call
+ mx_call_func_custom_types 
+---------------------------
+ (S,S)
+(1 row)
+
+select squares(4);
+DEBUG:  pushing down the function call
+ERROR:  input of anonymous composite types is not implemented
+select multi_mx_function_call_delegation.mx_call_func(2, 0);
+DEBUG:  pushing down the function call
+ mx_call_func 
+--------------
+           28
+(1 row)
+
+select multi_mx_function_call_delegation.mx_call_func_custom_types('S', 'A');
+DEBUG:  pushing down the function call
+ mx_call_func_custom_types 
+---------------------------
+ (S,S)
+(1 row)
+
+-- We don't allow distributing calls inside transactions
+begin;
+select mx_call_func(2, 0);
+DEBUG:  not pushing down function calls in a multi-statement transaction
+DEBUG:  generating subplan 12_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_function_call_delegation.mx_call_dist_table_1 t1 JOIN multi_mx_function_call_delegation.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  Plan 12 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('12_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+ mx_call_func 
+--------------
+           29
+(1 row)
+
+commit;
+-- Drop the table colocated with mx_call_func_custom_types. Now it shouldn't
+-- be routed to workers anymore.
+SET client_min_messages TO NOTICE;
+drop table mx_call_dist_table_enum;
+SET client_min_messages TO DEBUG1;
+select mx_call_func_custom_types('S', 'A');
+DEBUG:  function does not have co-located tables
+ mx_call_func_custom_types 
+---------------------------
+ (F,S)
+(1 row)
+
+-- Make sure we do bounds checking on distributed argument index
+-- This also tests that we have cache invalidation for pg_dist_object updates
+select colocate_proc_with_table('mx_call_func', 'mx_call_dist_table_1'::regclass, -1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
+select mx_call_func(2, 0);
+DEBUG:  function call does not have a distribution argument
+DEBUG:  generating subplan 14_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_function_call_delegation.mx_call_dist_table_1 t1 JOIN multi_mx_function_call_delegation.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  Plan 14 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('14_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+ mx_call_func 
+--------------
+           29
+(1 row)
+
+select colocate_proc_with_table('mx_call_func', 'mx_call_dist_table_1'::regclass, 2);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
+select mx_call_func(2, 0);
+DEBUG:  function call does not have a distribution argument
+DEBUG:  generating subplan 17_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_function_call_delegation.mx_call_dist_table_1 t1 JOIN multi_mx_function_call_delegation.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  Plan 17 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('17_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+ mx_call_func 
+--------------
+           29
+(1 row)
+
+-- We don't currently support colocating with reference tables
+select colocate_proc_with_table('mx_call_func', 'mx_call_dist_table_ref'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
+select mx_call_func(2, 0);
+DEBUG:  cannnot push down function call for reference tables
+DEBUG:  generating subplan 19_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_function_call_delegation.mx_call_dist_table_1 t1 JOIN multi_mx_function_call_delegation.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  Plan 19 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('19_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+ mx_call_func 
+--------------
+           29
+(1 row)
+
+-- We don't currently support colocating with replicated tables
+select colocate_proc_with_table('mx_call_func', 'mx_call_dist_table_replica'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
+select mx_call_func(2, 0);
+DEBUG:  cannot push down function call for replicated distributed tables
+DEBUG:  generating subplan 21_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_function_call_delegation.mx_call_dist_table_1 t1 JOIN multi_mx_function_call_delegation.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  Plan 21 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('21_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+ mx_call_func 
+--------------
+           29
+(1 row)
+
+SET client_min_messages TO NOTICE;
+drop table mx_call_dist_table_replica;
+SET client_min_messages TO DEBUG1;
+select colocate_proc_with_table('mx_call_func', 'mx_call_dist_table_1'::regclass, 1);
+ colocate_proc_with_table 
+--------------------------
+ 
+(1 row)
+
+-- Test table returning functions.
+CREATE FUNCTION mx_call_func_tbl(x int)
+RETURNS TABLE (p0 int, p1 int)
+LANGUAGE plpgsql AS $$
+BEGIN
+    INSERT INTO multi_mx_function_call_delegation.mx_call_dist_table_1 VALUES (x, -1), (x+1, 4);
+    UPDATE multi_mx_function_call_delegation.mx_call_dist_table_1 SET val = val+1 WHERE id >= x;
+    UPDATE multi_mx_function_call_delegation.mx_call_dist_table_1 SET val = val-1 WHERE id >= x;
+    RETURN QUERY
+        SELECT id, val
+        FROM multi_mx_function_call_delegation.mx_call_dist_table_1 t
+        WHERE id >= x
+        ORDER BY 1, 2;
+END;$$;
+-- before distribution ...
+select mx_call_func_tbl(10);
+ mx_call_func_tbl 
+------------------
+ (10,-1)
+ (11,4)
+(2 rows)
+
+-- after distribution ...
+select create_distributed_function('mx_call_func_tbl(int)', '$1', 'mx_call_dist_table_1');
+DEBUG:  switching to sequential query execution mode
+DETAIL:  A distributed function is created. To make sure subsequent commands see the type correctly we need to make sure to use only one connection for all future commands
+ create_distributed_function 
+-----------------------------
+ 
+(1 row)
+
+select mx_call_func_tbl(20);
+DEBUG:  pushing down the function call
+ mx_call_func_tbl 
+------------------
+ (20,-1)
+ (21,4)
+(2 rows)
+
+-- Test that we properly propagate errors raised from procedures.
+CREATE FUNCTION mx_call_func_raise(x int)
+RETURNS void LANGUAGE plpgsql AS $$
+BEGIN
+    RAISE WARNING 'warning';
+    RAISE EXCEPTION 'error';
+END;$$;
+select create_distributed_function('mx_call_func_raise(int)', '$1', 'mx_call_dist_table_1');
+DEBUG:  switching to sequential query execution mode
+DETAIL:  A distributed function is created. To make sure subsequent commands see the type correctly we need to make sure to use only one connection for all future commands
+ create_distributed_function 
+-----------------------------
+ 
+(1 row)
+
+select mx_call_func_raise(2);
+DEBUG:  pushing down the function call
+DEBUG:  warning
+DETAIL:  WARNING from localhost:57638
+ERROR:  error
+CONTEXT:  while executing command on localhost:57638
+PL/pgSQL function multi_mx_function_call_delegation.mx_call_func_raise(integer) line 4 at RAISE
+-- Test that we don't propagate to non-metadata worker nodes
+select stop_metadata_sync_to_node('localhost', :worker_1_port);
+ stop_metadata_sync_to_node 
+----------------------------
+ 
+(1 row)
+
+select stop_metadata_sync_to_node('localhost', :worker_2_port);
+ stop_metadata_sync_to_node 
+----------------------------
+ 
+(1 row)
+
+select mx_call_func(2, 0);
+DEBUG:  the worker node does not have metadata
+DEBUG:  generating subplan 27_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_function_call_delegation.mx_call_dist_table_1 t1 JOIN multi_mx_function_call_delegation.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  Plan 27 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('27_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+ mx_call_func 
+--------------
+           29
+(1 row)
+
+SET client_min_messages TO NOTICE;
+select start_metadata_sync_to_node('localhost', :worker_1_port);
+ start_metadata_sync_to_node 
+-----------------------------
+ 
+(1 row)
+
+select start_metadata_sync_to_node('localhost', :worker_2_port);
+ start_metadata_sync_to_node 
+-----------------------------
+ 
+(1 row)
+
+-- stop_metadata_sync_to_node()/start_metadata_sync_to_node() might make
+-- worker backend caches inconsistent. Reconnect to coordinator to use
+-- new worker connections, hence new backends.
+\c - - - :master_port
+SET search_path to multi_mx_function_call_delegation, public;
+SET client_min_messages TO DEBUG1;
+--
+-- Test non-const parameter values
+--
+CREATE FUNCTION mx_call_add(int, int) RETURNS int
+    AS 'select $1 + $2;' LANGUAGE SQL IMMUTABLE;
+SELECT create_distributed_function('mx_call_add(int,int)', '$1');
+DEBUG:  switching to sequential query execution mode
+DETAIL:  A distributed function is created. To make sure subsequent commands see the type correctly we need to make sure to use only one connection for all future commands
+ create_distributed_function 
+-----------------------------
+ 
+(1 row)
+
+-- subquery parameters cannot be pushed down
+select mx_call_func((select x + 1 from mx_call_add(3, 4) x), 2);
+DEBUG:  arguments in a distributed function must not contain subqueries
+DEBUG:  generating subplan 1_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_function_call_delegation.mx_call_dist_table_1 t1 JOIN multi_mx_function_call_delegation.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  Plan 1 query after replacing subqueries and CTEs: SELECT (9 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('1_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+ mx_call_func 
+--------------
+           35
+(1 row)
+
+-- volatile parameter cannot be pushed down
+select mx_call_func(floor(random())::int, 2);
+DEBUG:  arguments in a distributed function must be constant expressions
+DEBUG:  generating subplan 3_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_function_call_delegation.mx_call_dist_table_1 t1 JOIN multi_mx_function_call_delegation.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  Plan 3 query after replacing subqueries and CTEs: SELECT (1 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('3_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+ mx_call_func 
+--------------
+           27
+(1 row)
+
+-- test forms we don't distribute
+select * from mx_call_func(2, 0);
+DEBUG:  generating subplan 5_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_function_call_delegation.mx_call_dist_table_1 t1 JOIN multi_mx_function_call_delegation.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  Plan 5 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('5_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+ y  
+----
+ 29
+(1 row)
+
+select mx_call_func(2, 0) from mx_call_dist_table_1;
+ mx_call_func 
+--------------
+           28
+           28
+           28
+           28
+           28
+           28
+           28
+           28
+           28
+(9 rows)
+
+select mx_call_func(2, 0) where mx_call_func(0, 2) = 0;
+DEBUG:  generating subplan 8_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_function_call_delegation.mx_call_dist_table_1 t1 JOIN multi_mx_function_call_delegation.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  Plan 8 query after replacing subqueries and CTEs: SELECT (1 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('8_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+ mx_call_func 
+--------------
+(0 rows)
+
+select mx_call_func(2, 0), mx_call_func(0, 2);
+DEBUG:  generating subplan 10_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_function_call_delegation.mx_call_dist_table_1 t1 JOIN multi_mx_function_call_delegation.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  Plan 10 query after replacing subqueries and CTEs: SELECT (3 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('10_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  generating subplan 13_1 for subquery SELECT sum((t1.val OPERATOR(pg_catalog.+) t2.val)) AS sum FROM (multi_mx_function_call_delegation.mx_call_dist_table_1 t1 JOIN multi_mx_function_call_delegation.mx_call_dist_table_2 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.id)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+DEBUG:  Plan 13 query after replacing subqueries and CTEs: SELECT (1 OPERATOR(pg_catalog.+) (SELECT intermediate_result.sum FROM read_intermediate_result('13_1'::text, 'binary'::citus_copy_format) intermediate_result(sum bigint)))
+CONTEXT:  SQL statement "SELECT y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id)"
+PL/pgSQL function mx_call_func(integer,integer) line 8 at assignment
+ mx_call_func | mx_call_func 
+--------------+--------------
+           29 |           27
+(1 row)
+
+DO $$ BEGIN perform mx_call_func_tbl(40); END; $$;
+DEBUG:  not pushing down function calls in a multi-statement transaction
+CONTEXT:  SQL statement "SELECT mx_call_func_tbl(40)"
+PL/pgSQL function inline_code_block line 1 at PERFORM
+SELECT * FROM mx_call_dist_table_1 WHERE id >= 40 ORDER BY id, val;
+ id | val 
+----+-----
+ 40 |  -1
+ 41 |   4
+(2 rows)
+
+-- Prepared statements
+PREPARE call_plan (int, int) AS SELECT mx_call_func($1, $2);
+EXECUTE call_plan(2, 0);
+DEBUG:  pushing down the function call
+ mx_call_func 
+--------------
+           28
+(1 row)
+
+RESET client_min_messages;
+\set VERBOSITY terse
+DROP SCHEMA multi_mx_function_call_delegation CASCADE;
+NOTICE:  drop cascades to 10 other objects
diff --git a/src/test/regress/expected/multi_test_helpers.out b/src/test/regress/expected/multi_test_helpers.out
index 240872882..799324e22 100644
--- a/src/test/regress/expected/multi_test_helpers.out
+++ b/src/test/regress/expected/multi_test_helpers.out
@@ -140,3 +140,13 @@ BEGIN
      EXECUTE p_sql;
      PERFORM run_command_on_workers(p_sql);
 END;$$;
+-- 1. Marks the given procedure as colocated with the given table.
+-- 2. Marks the argument index with which we route the procedure.
+CREATE FUNCTION colocate_proc_with_table(procname text, tablerelid regclass, argument_index int)
+RETURNS void LANGUAGE plpgsql AS $$
+BEGIN
+    update citus.pg_dist_object
+    set distribution_argument_index = argument_index, colocationid = pg_dist_partition.colocationid
+    from pg_proc, pg_dist_partition
+    where proname = procname and oid = objid and pg_dist_partition.logicalrelid = tablerelid;
+END;$$;
diff --git a/src/test/regress/multi_mx_schedule b/src/test/regress/multi_mx_schedule
index 6e19b1f57..eca2b9f26 100644
--- a/src/test/regress/multi_mx_schedule
+++ b/src/test/regress/multi_mx_schedule
@@ -33,6 +33,7 @@ test: multi_mx_repartition_udt_prepare mx_foreign_key_to_reference_table
 test: multi_mx_repartition_join_w1 multi_mx_repartition_join_w2 multi_mx_repartition_udt_w1 multi_mx_repartition_udt_w2
 test: multi_mx_metadata 
 test: multi_mx_call
+test: multi_mx_function_call_delegation
 test: multi_mx_modifications local_shard_execution
 test: multi_mx_transaction_recovery
 test: multi_mx_modifying_xacts
diff --git a/src/test/regress/sql/multi_mx_call.sql b/src/test/regress/sql/multi_mx_call.sql
index c6caf7698..53883b63e 100644
--- a/src/test/regress/sql/multi_mx_call.sql
+++ b/src/test/regress/sql/multi_mx_call.sql
@@ -1,5 +1,8 @@
 -- Test passing off CALL to mx workers
 
+create schema multi_mx_call;
+set search_path to multi_mx_call, public;
+
 -- Create worker-local tables to test procedure calls were routed
 
 set citus.shard_replication_factor to 2;
@@ -13,25 +16,6 @@ insert into mx_call_dist_table_replica values (9,1),(8,2),(7,3),(6,4),(5,5);
 set citus.shard_replication_factor to 1;
 set citus.replication_model to 'streaming';
 
-create schema multi_mx_call;
-set search_path to multi_mx_call, public;
-
---
--- Utility UDFs
---
-
--- 1. Marks the given procedure as colocated with the given table.
--- 2. Marks the argument index with which we route the procedure.
-CREATE PROCEDURE colocate_proc_with_table(procname text, tablerelid regclass, argument_index int)
-LANGUAGE plpgsql AS $$
-BEGIN
-    update citus.pg_dist_object
-    set distribution_argument_index = argument_index, colocationid = pg_dist_partition.colocationid
-    from pg_proc, pg_dist_partition
-    where proname = procname and oid = objid and pg_dist_partition.logicalrelid = tablerelid;
-END;$$;
-
-
 --
 -- Create tables and procedures we want to use in tests
 --
@@ -78,6 +62,10 @@ END;$$;
 call multi_mx_call.mx_call_proc(2, 0);
 call multi_mx_call.mx_call_proc_custom_types('S', 'A');
 
+-- Same for unqualified names
+call mx_call_proc(2, 0);
+call mx_call_proc_custom_types('S', 'A');
+
 -- Mark both procedures as distributed ...
 select create_distributed_function('mx_call_proc(int,int)');
 select create_distributed_function('mx_call_proc_custom_types(mx_call_enum,mx_call_enum)');
@@ -89,10 +77,13 @@ call multi_mx_call.mx_call_proc(2, 0);
 call multi_mx_call.mx_call_proc_custom_types('S', 'A');
 
 -- Mark them as colocated with a table. Now we should route them to workers.
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 1);
-call multi_mx_call.colocate_proc_with_table('mx_call_proc_custom_types', 'mx_call_dist_table_enum'::regclass, 1);
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 1);
+select colocate_proc_with_table('mx_call_proc_custom_types', 'mx_call_dist_table_enum'::regclass, 1);
+
 call multi_mx_call.mx_call_proc(2, 0);
 call multi_mx_call.mx_call_proc_custom_types('S', 'A');
+call mx_call_proc(2, 0);
+call mx_call_proc_custom_types('S', 'A');
 
 -- We don't allow distributing calls inside transactions
 begin;
@@ -108,34 +99,34 @@ call multi_mx_call.mx_call_proc_custom_types('S', 'A');
 
 -- Make sure we do bounds checking on distributed argument index
 -- This also tests that we have cache invalidation for pg_dist_object updates
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, -1);
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, -1);
 call multi_mx_call.mx_call_proc(2, 0);
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 2);
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 2);
 call multi_mx_call.mx_call_proc(2, 0);
 
 -- We don't currently support colocating with reference tables
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_ref'::regclass, 1);
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_ref'::regclass, 1);
 call multi_mx_call.mx_call_proc(2, 0);
 
 -- We don't currently support colocating with replicated tables
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_replica'::regclass, 1);
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_replica'::regclass, 1);
 call multi_mx_call.mx_call_proc(2, 0);
 SET client_min_messages TO NOTICE;
 drop table mx_call_dist_table_replica;
 SET client_min_messages TO DEBUG1;
 
-call multi_mx_call.colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 1);
+select colocate_proc_with_table('mx_call_proc', 'mx_call_dist_table_1'::regclass, 1);
 
 -- Test that we handle transactional constructs correctly inside a procedure
 -- that is routed to the workers.
 CREATE PROCEDURE mx_call_proc_tx(x int) LANGUAGE plpgsql AS $$
 BEGIN
-    INSERT INTO mx_call_dist_table_1 VALUES (x, -1), (x+1, 4);
+    INSERT INTO multi_mx_call.mx_call_dist_table_1 VALUES (x, -1), (x+1, 4);
     COMMIT;
-    UPDATE mx_call_dist_table_1 SET val = val+1 WHERE id >= x;
+    UPDATE multi_mx_call.mx_call_dist_table_1 SET val = val+1 WHERE id >= x;
     ROLLBACK;
     -- Now do the final update!
-    UPDATE mx_call_dist_table_1 SET val = val-1 WHERE id >= x;
+    UPDATE multi_mx_call.mx_call_dist_table_1 SET val = val-1 WHERE id >= x;
 END;$$;
 
 -- before distribution ...
@@ -162,6 +153,12 @@ call multi_mx_call.mx_call_proc(2, 0);
 SET client_min_messages TO NOTICE;
 select start_metadata_sync_to_node('localhost', :worker_1_port);
 select start_metadata_sync_to_node('localhost', :worker_2_port);
+
+-- stop_metadata_sync_to_node()/start_metadata_sync_to_node() might make
+-- worker backend caches inconsistent. Reconnect to coordinator to use
+-- new worker connections, hence new backends.
+\c - - - :master_port
+SET search_path to multi_mx_call, public;
 SET client_min_messages TO DEBUG1;
 
 --
diff --git a/src/test/regress/sql/multi_mx_function_call_delegation.sql b/src/test/regress/sql/multi_mx_function_call_delegation.sql
new file mode 100644
index 000000000..ddf92f9bf
--- /dev/null
+++ b/src/test/regress/sql/multi_mx_function_call_delegation.sql
@@ -0,0 +1,198 @@
+-- Test passing off function call to mx workers
+
+CREATE SCHEMA multi_mx_function_call_delegation;
+SET search_path TO multi_mx_function_call_delegation, public;
+
+SET citus.shard_replication_factor TO 2;
+SET citus.replication_model TO 'statement';
+
+-- This table requires specific settings, create before getting into things
+create table mx_call_dist_table_replica(id int, val int);
+select create_distributed_table('mx_call_dist_table_replica', 'id');
+insert into mx_call_dist_table_replica values (9,1),(8,2),(7,3),(6,4),(5,5);
+
+SET citus.shard_replication_factor TO 1;
+SET citus.replication_model TO 'streaming';
+
+--
+-- Create tables and functions we want to use in tests
+--
+create table mx_call_dist_table_1(id int, val int);
+select create_distributed_table('mx_call_dist_table_1', 'id');
+insert into mx_call_dist_table_1 values (3,1),(4,5),(9,2),(6,5),(3,5);
+
+create table mx_call_dist_table_2(id int, val int);
+select create_distributed_table('mx_call_dist_table_2', 'id');
+insert into mx_call_dist_table_2 values (1,1),(1,2),(2,2),(3,3),(3,4);
+
+create table mx_call_dist_table_ref(id int, val int);
+select create_reference_table('mx_call_dist_table_ref');
+insert into mx_call_dist_table_ref values (2,7),(1,8),(2,8),(1,8),(2,8);
+
+create type mx_call_enum as enum ('A', 'S', 'D', 'F');
+create table mx_call_dist_table_enum(id int, key mx_call_enum);
+select create_distributed_table('mx_call_dist_table_enum', 'key');
+insert into mx_call_dist_table_enum values (1,'S'),(2,'A'),(3,'D'),(4,'F');
+
+CREATE FUNCTION squares(int) RETURNS SETOF RECORD
+    AS $$ SELECT i, i * i FROM generate_series(1, $1) i $$
+    LANGUAGE SQL;
+
+CREATE FUNCTION mx_call_func(x int, INOUT y int)
+LANGUAGE plpgsql AS $$
+BEGIN
+    -- groupid is 0 in coordinator and non-zero in workers, so by using it here
+    -- we make sure the function is being executed in the worker.
+    y := x + (select case groupid when 0 then 1 else 0 end from pg_dist_local_group);
+    -- we also make sure that we can run distributed queries in the functions
+    -- that are routed to the workers.
+    y := y + (select sum(t1.val + t2.val) from multi_mx_function_call_delegation.mx_call_dist_table_1 t1 join multi_mx_function_call_delegation.mx_call_dist_table_2 t2 on t1.id = t2.id);
+END;$$;
+
+-- create another function which verifies:
+-- 1. we work fine with multiple return columns
+-- 2. we work fine in combination with custom types
+CREATE FUNCTION mx_call_func_custom_types(INOUT x mx_call_enum, INOUT y mx_call_enum)
+LANGUAGE plpgsql AS $$
+BEGIN
+    y := x;
+    x := (select case groupid when 0 then 'F' else 'S' end from pg_dist_local_group);
+END;$$;
+
+-- Test that undistributed functions have no issue executing
+select multi_mx_function_call_delegation.mx_call_func(2, 0);
+select multi_mx_function_call_delegation.mx_call_func_custom_types('S', 'A');
+select squares(4);
+
+-- Same for unqualified name
+select mx_call_func(2, 0);
+
+-- Mark both functions as distributed ...
+select create_distributed_function('mx_call_func(int,int)');
+select create_distributed_function('mx_call_func_custom_types(mx_call_enum,mx_call_enum)');
+select create_distributed_function('squares(int)');
+
+-- We still don't route them to the workers, because they aren't
+-- colocated with any distributed tables.
+SET client_min_messages TO DEBUG1;
+select mx_call_func(2, 0);
+select mx_call_func_custom_types('S', 'A');
+
+-- Mark them as colocated with a table. Now we should route them to workers.
+select colocate_proc_with_table('mx_call_func', 'mx_call_dist_table_1'::regclass, 1);
+select colocate_proc_with_table('mx_call_func_custom_types', 'mx_call_dist_table_enum'::regclass, 1);
+select colocate_proc_with_table('squares', 'mx_call_dist_table_2'::regclass, 0);
+
+select mx_call_func(2, 0);
+select mx_call_func_custom_types('S', 'A');
+select squares(4);
+select multi_mx_function_call_delegation.mx_call_func(2, 0);
+select multi_mx_function_call_delegation.mx_call_func_custom_types('S', 'A');
+
+-- We don't allow distributing calls inside transactions
+begin;
+select mx_call_func(2, 0);
+commit;
+
+-- Drop the table colocated with mx_call_func_custom_types. Now it shouldn't
+-- be routed to workers anymore.
+SET client_min_messages TO NOTICE;
+drop table mx_call_dist_table_enum;
+SET client_min_messages TO DEBUG1;
+select mx_call_func_custom_types('S', 'A');
+
+-- Make sure we do bounds checking on distributed argument index
+-- This also tests that we have cache invalidation for pg_dist_object updates
+select colocate_proc_with_table('mx_call_func', 'mx_call_dist_table_1'::regclass, -1);
+select mx_call_func(2, 0);
+select colocate_proc_with_table('mx_call_func', 'mx_call_dist_table_1'::regclass, 2);
+select mx_call_func(2, 0);
+
+-- We don't currently support colocating with reference tables
+select colocate_proc_with_table('mx_call_func', 'mx_call_dist_table_ref'::regclass, 1);
+select mx_call_func(2, 0);
+
+-- We don't currently support colocating with replicated tables
+select colocate_proc_with_table('mx_call_func', 'mx_call_dist_table_replica'::regclass, 1);
+select mx_call_func(2, 0);
+SET client_min_messages TO NOTICE;
+drop table mx_call_dist_table_replica;
+SET client_min_messages TO DEBUG1;
+
+select colocate_proc_with_table('mx_call_func', 'mx_call_dist_table_1'::regclass, 1);
+
+-- Test table returning functions.
+CREATE FUNCTION mx_call_func_tbl(x int)
+RETURNS TABLE (p0 int, p1 int)
+LANGUAGE plpgsql AS $$
+BEGIN
+    INSERT INTO multi_mx_function_call_delegation.mx_call_dist_table_1 VALUES (x, -1), (x+1, 4);
+    UPDATE multi_mx_function_call_delegation.mx_call_dist_table_1 SET val = val+1 WHERE id >= x;
+    UPDATE multi_mx_function_call_delegation.mx_call_dist_table_1 SET val = val-1 WHERE id >= x;
+    RETURN QUERY
+        SELECT id, val
+        FROM multi_mx_function_call_delegation.mx_call_dist_table_1 t
+        WHERE id >= x
+        ORDER BY 1, 2;
+END;$$;
+
+-- before distribution ...
+select mx_call_func_tbl(10);
+-- after distribution ...
+select create_distributed_function('mx_call_func_tbl(int)', '$1', 'mx_call_dist_table_1');
+select mx_call_func_tbl(20);
+
+-- Test that we properly propagate errors raised from procedures.
+CREATE FUNCTION mx_call_func_raise(x int)
+RETURNS void LANGUAGE plpgsql AS $$
+BEGIN
+    RAISE WARNING 'warning';
+    RAISE EXCEPTION 'error';
+END;$$;
+select create_distributed_function('mx_call_func_raise(int)', '$1', 'mx_call_dist_table_1');
+select mx_call_func_raise(2);
+
+-- Test that we don't propagate to non-metadata worker nodes
+select stop_metadata_sync_to_node('localhost', :worker_1_port);
+select stop_metadata_sync_to_node('localhost', :worker_2_port);
+select mx_call_func(2, 0);
+SET client_min_messages TO NOTICE;
+select start_metadata_sync_to_node('localhost', :worker_1_port);
+select start_metadata_sync_to_node('localhost', :worker_2_port);
+
+-- stop_metadata_sync_to_node()/start_metadata_sync_to_node() might make
+-- worker backend caches inconsistent. Reconnect to coordinator to use
+-- new worker connections, hence new backends.
+\c - - - :master_port
+SET search_path to multi_mx_function_call_delegation, public;
+SET client_min_messages TO DEBUG1;
+
+--
+-- Test non-const parameter values
+--
+CREATE FUNCTION mx_call_add(int, int) RETURNS int
+    AS 'select $1 + $2;' LANGUAGE SQL IMMUTABLE;
+SELECT create_distributed_function('mx_call_add(int,int)', '$1');
+
+-- subquery parameters cannot be pushed down
+select mx_call_func((select x + 1 from mx_call_add(3, 4) x), 2);
+
+-- volatile parameter cannot be pushed down
+select mx_call_func(floor(random())::int, 2);
+
+-- test forms we don't distribute
+select * from mx_call_func(2, 0);
+select mx_call_func(2, 0) from mx_call_dist_table_1;
+select mx_call_func(2, 0) where mx_call_func(0, 2) = 0;
+select mx_call_func(2, 0), mx_call_func(0, 2);
+
+DO $$ BEGIN perform mx_call_func_tbl(40); END; $$;
+SELECT * FROM mx_call_dist_table_1 WHERE id >= 40 ORDER BY id, val;
+
+-- Prepared statements
+PREPARE call_plan (int, int) AS SELECT mx_call_func($1, $2);
+EXECUTE call_plan(2, 0);
+
+RESET client_min_messages;
+\set VERBOSITY terse
+DROP SCHEMA multi_mx_function_call_delegation CASCADE;
diff --git a/src/test/regress/sql/multi_test_helpers.sql b/src/test/regress/sql/multi_test_helpers.sql
index 7582f1ee1..0e853971d 100644
--- a/src/test/regress/sql/multi_test_helpers.sql
+++ b/src/test/regress/sql/multi_test_helpers.sql
@@ -140,3 +140,16 @@ BEGIN
      EXECUTE p_sql;
      PERFORM run_command_on_workers(p_sql);
 END;$$;
+
+-- 1. Marks the given procedure as colocated with the given table.
+-- 2. Marks the argument index with which we route the procedure.
+CREATE FUNCTION colocate_proc_with_table(procname text, tablerelid regclass, argument_index int)
+RETURNS void LANGUAGE plpgsql AS $$
+BEGIN
+    update citus.pg_dist_object
+    set distribution_argument_index = argument_index, colocationid = pg_dist_partition.colocationid
+    from pg_proc, pg_dist_partition
+    where proname = procname and oid = objid and pg_dist_partition.logicalrelid = tablerelid;
+END;$$;
+
+