diff --git a/src/backend/commands/event_trigger.c b/src/backend/commands/event_trigger.c
index 1e8587502e..3c3fc2515b 100644
--- a/src/backend/commands/event_trigger.c
+++ b/src/backend/commands/event_trigger.c
@@ -1290,10 +1290,6 @@ Datum
 pg_event_trigger_dropped_objects(PG_FUNCTION_ARGS)
 {
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 	slist_iter	iter;
 
 	/*
@@ -1306,30 +1302,8 @@ pg_event_trigger_dropped_objects(PG_FUNCTION_ARGS)
 				 errmsg("%s can only be called in a sql_drop event trigger function",
 						"pg_event_trigger_dropped_objects()")));
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
 	/* Build tuplestore to hold the result rows */
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	slist_foreach(iter, &(currentEventTriggerState->SQLDropList))
 	{
@@ -1398,7 +1372,8 @@ pg_event_trigger_dropped_objects(PG_FUNCTION_ARGS)
 			nulls[i++] = true;
 		}
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+							 values, nulls);
 	}
 
 	return (Datum) 0;
@@ -1846,10 +1821,6 @@ Datum
 pg_event_trigger_ddl_commands(PG_FUNCTION_ARGS)
 {
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 	ListCell   *lc;
 
 	/*
@@ -1861,30 +1832,8 @@ pg_event_trigger_ddl_commands(PG_FUNCTION_ARGS)
 				 errmsg("%s can only be called in an event trigger function",
 						"pg_event_trigger_ddl_commands()")));
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
 	/* Build tuplestore to hold the result rows */
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	foreach(lc, currentEventTriggerState->commandList)
 	{
@@ -2055,7 +2004,8 @@ pg_event_trigger_ddl_commands(PG_FUNCTION_ARGS)
 				break;
 		}
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+							 values, nulls);
 	}
 
 	PG_RETURN_VOID();
diff --git a/src/backend/commands/extension.c b/src/backend/commands/extension.c
index 42503ef454..1013790dbb 100644
--- a/src/backend/commands/extension.c
+++ b/src/backend/commands/extension.c
@@ -1932,38 +1932,12 @@ Datum
 pg_available_extensions(PG_FUNCTION_ARGS)
 {
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 	char	   *location;
 	DIR		   *dir;
 	struct dirent *de;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
 	/* Build tuplestore to hold the result rows */
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	location = get_extension_control_directory();
 	dir = AllocateDir(location);
@@ -2015,7 +1989,8 @@ pg_available_extensions(PG_FUNCTION_ARGS)
 			else
 				values[2] = CStringGetTextDatum(control->comment);
 
-			tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+			tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+								 values, nulls);
 		}
 
 		FreeDir(dir);
@@ -2037,38 +2012,12 @@ Datum
 pg_available_extension_versions(PG_FUNCTION_ARGS)
 {
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 	char	   *location;
 	DIR		   *dir;
 	struct dirent *de;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
 	/* Build tuplestore to hold the result rows */
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	location = get_extension_control_directory();
 	dir = AllocateDir(location);
@@ -2103,7 +2052,8 @@ pg_available_extension_versions(PG_FUNCTION_ARGS)
 			control = read_extension_control_file(extname);
 
 			/* scan extension's script directory for install scripts */
-			get_available_versions_for_extension(control, tupstore, tupdesc);
+			get_available_versions_for_extension(control, rsinfo->setResult,
+												 rsinfo->setDesc);
 		}
 
 		FreeDir(dir);
@@ -2316,10 +2266,6 @@ pg_extension_update_paths(PG_FUNCTION_ARGS)
 {
 	Name		extname = PG_GETARG_NAME(0);
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 	List	   *evi_list;
 	ExtensionControlFile *control;
 	ListCell   *lc1;
@@ -2327,30 +2273,8 @@ pg_extension_update_paths(PG_FUNCTION_ARGS)
 	/* Check extension name validity before any filesystem access */
 	check_valid_extension_name(NameStr(*extname));
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
 	/* Build tuplestore to hold the result rows */
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	/* Read the extension's control file */
 	control = read_extension_control_file(NameStr(*extname));
@@ -2407,7 +2331,8 @@ pg_extension_update_paths(PG_FUNCTION_ARGS)
 				pfree(pathbuf.data);
 			}
 
-			tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+			tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+								 values, nulls);
 		}
 	}
 
diff --git a/src/backend/commands/prepare.c b/src/backend/commands/prepare.c
index dce30aed6c..d2d8ee120c 100644
--- a/src/backend/commands/prepare.c
+++ b/src/backend/commands/prepare.c
@@ -702,41 +702,12 @@ Datum
 pg_prepared_statement(PG_FUNCTION_ARGS)
 {
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
-
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	/* need to build tuplestore in query context */
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
 
 	/*
 	 * We put all the tuples into a tuplestore in one scan of the hashtable.
 	 * This avoids any issue of the hashtable possibly changing between calls.
 	 */
-	tupstore =
-		tuplestore_begin_heap(rsinfo->allowedModes & SFRM_Materialize_Random,
-							  false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	/* generate junk in short-term context */
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	/* hash table might be uninitialized */
 	if (prepared_queries)
@@ -761,7 +732,8 @@ pg_prepared_statement(PG_FUNCTION_ARGS)
 			values[5] = Int64GetDatumFast(prep_stmt->plansource->num_generic_plans);
 			values[6] = Int64GetDatumFast(prep_stmt->plansource->num_custom_plans);
 
-			tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+			tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+								 values, nulls);
 		}
 	}
 
diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index c3406c3b9d..cf222fc3e9 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -20,6 +20,7 @@
 #include "catalog/pg_user_mapping.h"
 #include "foreign/fdwapi.h"
 #include "foreign/foreign.h"
+#include "funcapi.h"
 #include "lib/stringinfo.h"
 #include "miscadmin.h"
 #include "utils/builtins.h"
@@ -510,38 +511,12 @@ pg_options_to_table(PG_FUNCTION_ARGS)
 	ListCell   *cell;
 	List	   *options;
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
-
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize) ||
-		rsinfo->expectedDesc == NULL)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
 
 	options = untransformRelOptions(array);
 	rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
 
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	/*
-	 * Now prepare the result set.
-	 */
-	tupdesc = CreateTupleDescCopy(rsinfo->expectedDesc);
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	/* prepare the result set */
+	SetSingleFuncCall(fcinfo, SRF_SINGLE_USE_EXPECTED);
 
 	foreach(cell, options)
 	{
@@ -561,7 +536,8 @@ pg_options_to_table(PG_FUNCTION_ARGS)
 			values[1] = (Datum) 0;
 			nulls[1] = true;
 		}
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+							 values, nulls);
 	}
 
 	return (Datum) 0;
diff --git a/src/backend/libpq/hba.c b/src/backend/libpq/hba.c
index d84a40b726..90953c38f3 100644
--- a/src/backend/libpq/hba.c
+++ b/src/backend/libpq/hba.c
@@ -1685,8 +1685,8 @@ parse_hba_line(TokenizedLine *tok_line, int elevel)
 	if (parsedline->auth_method == uaCert)
 	{
 		/*
-		 * For auth method cert, client certificate validation is mandatory, and it implies
-		 * the level of verify-full.
+		 * For auth method cert, client certificate validation is mandatory,
+		 * and it implies the level of verify-full.
 		 */
 		parsedline->clientcert = clientCertFull;
 	}
@@ -2703,47 +2703,19 @@ fill_hba_view(Tuplestorestate *tuple_store, TupleDesc tupdesc)
 Datum
 pg_hba_file_rules(PG_FUNCTION_ARGS)
 {
-	Tuplestorestate *tuple_store;
-	TupleDesc	tupdesc;
-	MemoryContext old_cxt;
 	ReturnSetInfo *rsi;
 
 	/*
-	 * We must use the Materialize mode to be safe against HBA file changes
-	 * while the cursor is open. It's also more efficient than having to look
-	 * up our current position in the parsed list every time.
+	 * Build tuplestore to hold the result rows.  We must use the Materialize
+	 * mode to be safe against HBA file changes while the cursor is open.
+	 * It's also more efficient than having to look up our current position in
+	 * the parsed list every time.
 	 */
-	rsi = (ReturnSetInfo *) fcinfo->resultinfo;
-
-	/* Check to see if caller supports us returning a tuplestore */
-	if (rsi == NULL || !IsA(rsi, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsi->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	rsi->returnMode = SFRM_Materialize;
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	/* Build tuplestore to hold the result rows */
-	old_cxt = MemoryContextSwitchTo(rsi->econtext->ecxt_per_query_memory);
-
-	tuple_store =
-		tuplestore_begin_heap(rsi->allowedModes & SFRM_Materialize_Random,
-							  false, work_mem);
-	rsi->setDesc = tupdesc;
-	rsi->setResult = tuple_store;
-
-	MemoryContextSwitchTo(old_cxt);
+	SetSingleFuncCall(fcinfo, 0);
 
 	/* Fill the tuplestore */
-	fill_hba_view(tuple_store, tupdesc);
+	rsi = (ReturnSetInfo *) fcinfo->resultinfo;
+	fill_hba_view(rsi->setResult, rsi->setDesc);
 
 	PG_RETURN_NULL();
 }
diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c
index 5a68d6dead..6f25b2c2ad 100644
--- a/src/backend/replication/logical/launcher.c
+++ b/src/backend/replication/logical/launcher.c
@@ -930,34 +930,8 @@ pg_stat_get_subscription(PG_FUNCTION_ARGS)
 	Oid			subid = PG_ARGISNULL(0) ? InvalidOid : PG_GETARG_OID(0);
 	int			i;
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	/* Make sure we get consistent view of the workers. */
 	LWLockAcquire(LogicalRepWorkerLock, LW_SHARED);
@@ -1010,7 +984,8 @@ pg_stat_get_subscription(PG_FUNCTION_ARGS)
 		else
 			values[7] = TimestampTzGetDatum(worker.reply_time);
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+							 values, nulls);
 
 		/*
 		 * If only a single subscription was requested, and we found it,
diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c
index 3bd770a3ba..6058d36e0d 100644
--- a/src/backend/replication/logical/logicalfuncs.c
+++ b/src/backend/replication/logical/logicalfuncs.c
@@ -142,25 +142,11 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin
 				 errmsg("options array must not be null")));
 	arr = PG_GETARG_ARRAYTYPE_P(3);
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
 	/* state to write output to */
 	p = palloc0(sizeof(DecodingOutputState));
 
 	p->binary_output = binary;
 
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &p->tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
 	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
 	oldcontext = MemoryContextSwitchTo(per_query_ctx);
 
@@ -203,10 +189,9 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin
 		}
 	}
 
-	p->tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = p->tupstore;
-	rsinfo->setDesc = p->tupdesc;
+	SetSingleFuncCall(fcinfo, 0);
+	p->tupstore = rsinfo->setResult;
+	p->tupdesc = rsinfo->setDesc;
 
 	/*
 	 * Compute the current end-of-wal.
diff --git a/src/backend/replication/logical/origin.c b/src/backend/replication/logical/origin.c
index 76055a8a03..0e38eff0f0 100644
--- a/src/backend/replication/logical/origin.c
+++ b/src/backend/replication/logical/origin.c
@@ -1482,40 +1482,13 @@ Datum
 pg_show_replication_origin_status(PG_FUNCTION_ARGS)
 {
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 	int			i;
 #define REPLICATION_ORIGIN_PROGRESS_COLS 4
 
 	/* we want to return 0 rows if slot is set to zero */
 	replorigin_check_prerequisites(false, true);
 
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	if (tupdesc->natts != REPLICATION_ORIGIN_PROGRESS_COLS)
-		elog(ERROR, "wrong function definition");
-
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
-
+	SetSingleFuncCall(fcinfo, 0);
 
 	/* prevent slots from being concurrently dropped */
 	LWLockAcquire(ReplicationOriginLock, LW_SHARED);
@@ -1565,7 +1538,8 @@ pg_show_replication_origin_status(PG_FUNCTION_ARGS)
 
 		LWLockRelease(&state->lock);
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+							 values, nulls);
 	}
 
 	LWLockRelease(ReplicationOriginLock);
diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c
index 886899afd2..ca945994ef 100644
--- a/src/backend/replication/slotfuncs.c
+++ b/src/backend/replication/slotfuncs.c
@@ -233,42 +233,16 @@ pg_get_replication_slots(PG_FUNCTION_ARGS)
 {
 #define PG_GET_REPLICATION_SLOTS_COLS 14
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 	XLogRecPtr	currlsn;
 	int			slotno;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
 	/*
 	 * We don't require any special permission to see this function's data
 	 * because nothing should be sensitive. The most critical being the slot
 	 * name, which shouldn't contain anything particularly sensitive.
 	 */
 
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	currlsn = GetXLogWriteRecPtr();
 
@@ -431,7 +405,8 @@ pg_get_replication_slots(PG_FUNCTION_ARGS)
 
 		Assert(i == PG_GET_REPLICATION_SLOTS_COLS);
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+							 values, nulls);
 	}
 
 	LWLockRelease(ReplicationSlotControlLock);
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index 5a718b1fe9..2d0292a092 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -3403,37 +3403,11 @@ pg_stat_get_wal_senders(PG_FUNCTION_ARGS)
 {
 #define PG_STAT_GET_WAL_SENDERS_COLS	12
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 	SyncRepStandbyData *sync_standbys;
 	int			num_standbys;
 	int			i;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	/*
 	 * Get the currently active synchronous standbys.  This could be out of
@@ -3577,7 +3551,8 @@ pg_stat_get_wal_senders(PG_FUNCTION_ARGS)
 				values[11] = TimestampTzGetDatum(replyTime);
 		}
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+							 values, nulls);
 	}
 
 	return (Datum) 0;
diff --git a/src/backend/storage/ipc/shmem.c b/src/backend/storage/ipc/shmem.c
index 1f023a3460..c1279960cd 100644
--- a/src/backend/storage/ipc/shmem.c
+++ b/src/backend/storage/ipc/shmem.c
@@ -537,39 +537,13 @@ pg_get_shmem_allocations(PG_FUNCTION_ARGS)
 {
 #define PG_GET_SHMEM_SIZES_COLS 4
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 	HASH_SEQ_STATUS hstat;
 	ShmemIndexEnt *ent;
 	Size		named_allocated = 0;
 	Datum		values[PG_GET_SHMEM_SIZES_COLS];
 	bool		nulls[PG_GET_SHMEM_SIZES_COLS];
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	LWLockAcquire(ShmemIndexLock, LW_SHARED);
 
@@ -585,7 +559,8 @@ pg_get_shmem_allocations(PG_FUNCTION_ARGS)
 		values[3] = Int64GetDatum(ent->allocated_size);
 		named_allocated += ent->allocated_size;
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+							 values, nulls);
 	}
 
 	/* output shared memory allocated but not counted via the shmem index */
@@ -593,7 +568,7 @@ pg_get_shmem_allocations(PG_FUNCTION_ARGS)
 	nulls[1] = true;
 	values[2] = Int64GetDatum(ShmemSegHdr->freeoffset - named_allocated);
 	values[3] = values[2];
-	tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+	tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 
 	/* output as-of-yet unused shared memory */
 	nulls[0] = true;
@@ -601,7 +576,7 @@ pg_get_shmem_allocations(PG_FUNCTION_ARGS)
 	nulls[1] = false;
 	values[2] = Int64GetDatum(ShmemSegHdr->totalsize - ShmemSegHdr->freeoffset);
 	values[3] = values[2];
-	tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+	tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 
 	LWLockRelease(ShmemIndexLock);
 
diff --git a/src/backend/utils/adt/datetime.c b/src/backend/utils/adt/datetime.c
index 7926258c06..ba0ec35ac5 100644
--- a/src/backend/utils/adt/datetime.c
+++ b/src/backend/utils/adt/datetime.c
@@ -4786,9 +4786,6 @@ Datum
 pg_timezone_names(PG_FUNCTION_ARGS)
 {
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	bool		randomAccess;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
 	pg_tzenum  *tzenum;
 	pg_tz	   *tz;
 	Datum		values[4];
@@ -4799,31 +4796,8 @@ pg_timezone_names(PG_FUNCTION_ARGS)
 	const char *tzn;
 	Interval   *resInterval;
 	struct pg_tm itm;
-	MemoryContext oldcontext;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_SYNTAX_ERROR),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
-	oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
-
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	randomAccess = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
-	tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	/* initialize timezone scanning code */
 	tzenum = pg_tzenumerate_start();
@@ -4865,7 +4839,7 @@ pg_timezone_names(PG_FUNCTION_ARGS)
 
 		values[3] = BoolGetDatum(tm.tm_isdst > 0);
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 	}
 
 	pg_tzenumerate_end(tzenum);
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index fe6863d8b4..1ed01620a1 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -477,12 +477,8 @@ pg_ls_dir(PG_FUNCTION_ARGS)
 	char	   *location;
 	bool		missing_ok = false;
 	bool		include_dot_dirs = false;
-	bool		randomAccess;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
 	DIR		   *dirdesc;
 	struct dirent *de;
-	MemoryContext oldcontext;
 
 	location = convert_and_check_filename(PG_GETARG_TEXT_PP(0));
 
@@ -495,29 +491,7 @@ pg_ls_dir(PG_FUNCTION_ARGS)
 			include_dot_dirs = PG_GETARG_BOOL(2);
 	}
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_SYNTAX_ERROR),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
-	oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
-
-	tupdesc = CreateTemplateTupleDesc(1);
-	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "pg_ls_dir", TEXTOID, -1, 0);
-
-	randomAccess = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
-	tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, SRF_SINGLE_USE_EXPECTED);
 
 	dirdesc = AllocateDir(location);
 	if (!dirdesc)
@@ -541,7 +515,8 @@ pg_ls_dir(PG_FUNCTION_ARGS)
 		values[0] = CStringGetTextDatum(de->d_name);
 		nulls[0] = false;
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+							 values, nulls);
 	}
 
 	FreeDir(dirdesc);
@@ -571,36 +546,10 @@ static Datum
 pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir, bool missing_ok)
 {
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	bool		randomAccess;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
 	DIR		   *dirdesc;
 	struct dirent *de;
-	MemoryContext oldcontext;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_SYNTAX_ERROR),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
-	oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
-
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	randomAccess = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
-	tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	/*
 	 * Now walk the directory.  Note that we must do this within a single SRF
@@ -648,7 +597,7 @@ pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir, bool missing_ok)
 		values[2] = TimestampTzGetDatum(time_t_to_timestamptz(attrib.st_mtime));
 		memset(nulls, 0, sizeof(nulls));
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 	}
 
 	FreeDir(dirdesc);
diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
index 2457061f97..29664aa6e4 100644
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -1909,9 +1909,6 @@ each_worker_jsonb(FunctionCallInfo fcinfo, const char *funcname, bool as_text)
 {
 	Jsonb	   *jb = PG_GETARG_JSONB_P(0);
 	ReturnSetInfo *rsi;
-	Tuplestorestate *tuple_store;
-	TupleDesc	tupdesc;
-	TupleDesc	ret_tdesc;
 	MemoryContext old_cxt,
 				tmp_cxt;
 	bool		skipNested = false;
@@ -1926,30 +1923,7 @@ each_worker_jsonb(FunctionCallInfo fcinfo, const char *funcname, bool as_text)
 						funcname)));
 
 	rsi = (ReturnSetInfo *) fcinfo->resultinfo;
-
-	if (!rsi || !IsA(rsi, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsi->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	rsi->returnMode = SFRM_Materialize;
-
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	old_cxt = MemoryContextSwitchTo(rsi->econtext->ecxt_per_query_memory);
-
-	ret_tdesc = CreateTupleDescCopy(tupdesc);
-	BlessTupleDesc(ret_tdesc);
-	tuple_store =
-		tuplestore_begin_heap(rsi->allowedModes & SFRM_Materialize_Random,
-							  false, work_mem);
-
-	MemoryContextSwitchTo(old_cxt);
+	SetSingleFuncCall(fcinfo, SRF_SINGLE_BLESS);
 
 	tmp_cxt = AllocSetContextCreate(CurrentMemoryContext,
 									"jsonb_each temporary cxt",
@@ -1964,7 +1938,6 @@ each_worker_jsonb(FunctionCallInfo fcinfo, const char *funcname, bool as_text)
 		if (r == WJB_KEY)
 		{
 			text	   *key;
-			HeapTuple	tuple;
 			Datum		values[2];
 			bool		nulls[2] = {false, false};
 
@@ -2001,9 +1974,7 @@ each_worker_jsonb(FunctionCallInfo fcinfo, const char *funcname, bool as_text)
 				values[1] = PointerGetDatum(val);
 			}
 
-			tuple = heap_form_tuple(ret_tdesc, values, nulls);
-
-			tuplestore_puttuple(tuple_store, tuple);
+			tuplestore_putvalues(rsi->setResult, rsi->setDesc, values, nulls);
 
 			/* clean up and switch back */
 			MemoryContextSwitchTo(old_cxt);
@@ -2013,9 +1984,6 @@ each_worker_jsonb(FunctionCallInfo fcinfo, const char *funcname, bool as_text)
 
 	MemoryContextDelete(tmp_cxt);
 
-	rsi->setResult = tuple_store;
-	rsi->setDesc = ret_tdesc;
-
 	PG_RETURN_NULL();
 }
 
@@ -2027,8 +1995,6 @@ each_worker(FunctionCallInfo fcinfo, bool as_text)
 	JsonLexContext *lex;
 	JsonSemAction *sem;
 	ReturnSetInfo *rsi;
-	MemoryContext old_cxt;
-	TupleDesc	tupdesc;
 	EachState  *state;
 
 	lex = makeJsonLexContext(json, true);
@@ -2037,30 +2003,9 @@ each_worker(FunctionCallInfo fcinfo, bool as_text)
 
 	rsi = (ReturnSetInfo *) fcinfo->resultinfo;
 
-	if (!rsi || !IsA(rsi, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-
-	if (!(rsi->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	rsi->returnMode = SFRM_Materialize;
-
-	(void) get_call_result_type(fcinfo, NULL, &tupdesc);
-
-	/* make these in a sufficiently long-lived memory context */
-	old_cxt = MemoryContextSwitchTo(rsi->econtext->ecxt_per_query_memory);
-
-	state->ret_tdesc = CreateTupleDescCopy(tupdesc);
-	BlessTupleDesc(state->ret_tdesc);
-	state->tuple_store =
-		tuplestore_begin_heap(rsi->allowedModes & SFRM_Materialize_Random,
-							  false, work_mem);
-
-	MemoryContextSwitchTo(old_cxt);
+	SetSingleFuncCall(fcinfo, SRF_SINGLE_BLESS);
+	state->tuple_store = rsi->setResult;
+	state->ret_tdesc = rsi->setDesc;
 
 	sem->semstate = (void *) state;
 	sem->array_start = each_array_start;
@@ -2079,9 +2024,6 @@ each_worker(FunctionCallInfo fcinfo, bool as_text)
 
 	MemoryContextDelete(state->tmp_cxt);
 
-	rsi->setResult = state->tuple_store;
-	rsi->setDesc = state->ret_tdesc;
-
 	PG_RETURN_NULL();
 }
 
@@ -2206,9 +2148,6 @@ elements_worker_jsonb(FunctionCallInfo fcinfo, const char *funcname,
 {
 	Jsonb	   *jb = PG_GETARG_JSONB_P(0);
 	ReturnSetInfo *rsi;
-	Tuplestorestate *tuple_store;
-	TupleDesc	tupdesc;
-	TupleDesc	ret_tdesc;
 	MemoryContext old_cxt,
 				tmp_cxt;
 	bool		skipNested = false;
@@ -2227,31 +2166,8 @@ elements_worker_jsonb(FunctionCallInfo fcinfo, const char *funcname,
 
 	rsi = (ReturnSetInfo *) fcinfo->resultinfo;
 
-	if (!rsi || !IsA(rsi, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-
-	if (!(rsi->allowedModes & SFRM_Materialize) ||
-		rsi->expectedDesc == NULL)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	rsi->returnMode = SFRM_Materialize;
-
-	/* it's a simple type, so don't use get_call_result_type() */
-	tupdesc = rsi->expectedDesc;
-
-	old_cxt = MemoryContextSwitchTo(rsi->econtext->ecxt_per_query_memory);
-
-	ret_tdesc = CreateTupleDescCopy(tupdesc);
-	BlessTupleDesc(ret_tdesc);
-	tuple_store =
-		tuplestore_begin_heap(rsi->allowedModes & SFRM_Materialize_Random,
-							  false, work_mem);
-
-	MemoryContextSwitchTo(old_cxt);
+	SetSingleFuncCall(fcinfo,
+					  SRF_SINGLE_USE_EXPECTED | SRF_SINGLE_BLESS);
 
 	tmp_cxt = AllocSetContextCreate(CurrentMemoryContext,
 									"jsonb_array_elements temporary cxt",
@@ -2265,7 +2181,6 @@ elements_worker_jsonb(FunctionCallInfo fcinfo, const char *funcname,
 
 		if (r == WJB_ELEM)
 		{
-			HeapTuple	tuple;
 			Datum		values[1];
 			bool		nulls[1] = {false};
 
@@ -2291,9 +2206,7 @@ elements_worker_jsonb(FunctionCallInfo fcinfo, const char *funcname,
 				values[0] = PointerGetDatum(val);
 			}
 
-			tuple = heap_form_tuple(ret_tdesc, values, nulls);
-
-			tuplestore_puttuple(tuple_store, tuple);
+			tuplestore_putvalues(rsi->setResult, rsi->setDesc, values, nulls);
 
 			/* clean up and switch back */
 			MemoryContextSwitchTo(old_cxt);
@@ -2303,9 +2216,6 @@ elements_worker_jsonb(FunctionCallInfo fcinfo, const char *funcname,
 
 	MemoryContextDelete(tmp_cxt);
 
-	rsi->setResult = tuple_store;
-	rsi->setDesc = ret_tdesc;
-
 	PG_RETURN_NULL();
 }
 
@@ -2330,41 +2240,15 @@ elements_worker(FunctionCallInfo fcinfo, const char *funcname, bool as_text)
 	JsonLexContext *lex = makeJsonLexContext(json, as_text);
 	JsonSemAction *sem;
 	ReturnSetInfo *rsi;
-	MemoryContext old_cxt;
-	TupleDesc	tupdesc;
 	ElementsState *state;
 
 	state = palloc0(sizeof(ElementsState));
 	sem = palloc0(sizeof(JsonSemAction));
 
+	SetSingleFuncCall(fcinfo, SRF_SINGLE_USE_EXPECTED | SRF_SINGLE_BLESS);
 	rsi = (ReturnSetInfo *) fcinfo->resultinfo;
-
-	if (!rsi || !IsA(rsi, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-
-	if (!(rsi->allowedModes & SFRM_Materialize) ||
-		rsi->expectedDesc == NULL)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	rsi->returnMode = SFRM_Materialize;
-
-	/* it's a simple type, so don't use get_call_result_type() */
-	tupdesc = rsi->expectedDesc;
-
-	/* make these in a sufficiently long-lived memory context */
-	old_cxt = MemoryContextSwitchTo(rsi->econtext->ecxt_per_query_memory);
-
-	state->ret_tdesc = CreateTupleDescCopy(tupdesc);
-	BlessTupleDesc(state->ret_tdesc);
-	state->tuple_store =
-		tuplestore_begin_heap(rsi->allowedModes & SFRM_Materialize_Random,
-							  false, work_mem);
-
-	MemoryContextSwitchTo(old_cxt);
+	state->tuple_store = rsi->setResult;
+	state->ret_tdesc = rsi->setDesc;
 
 	sem->semstate = (void *) state;
 	sem->object_start = elements_object_start;
@@ -2384,9 +2268,6 @@ elements_worker(FunctionCallInfo fcinfo, const char *funcname, bool as_text)
 
 	MemoryContextDelete(state->tmp_cxt);
 
-	rsi->setResult = state->tuple_store;
-	rsi->setDesc = state->ret_tdesc;
-
 	PG_RETURN_NULL();
 }
 
diff --git a/src/backend/utils/adt/mcxtfuncs.c b/src/backend/utils/adt/mcxtfuncs.c
index c7c95adf97..bb7cc94024 100644
--- a/src/backend/utils/adt/mcxtfuncs.c
+++ b/src/backend/utils/adt/mcxtfuncs.c
@@ -120,36 +120,9 @@ Datum
 pg_get_backend_memory_contexts(PG_FUNCTION_ARGS)
 {
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
-
-	PutMemoryContextsStatsTupleStore(tupstore, tupdesc,
+	SetSingleFuncCall(fcinfo, 0);
+	PutMemoryContextsStatsTupleStore(rsinfo->setResult, rsinfo->setDesc,
 									 TopMemoryContext, NULL, 0);
 
 	return (Datum) 0;
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index e79eb6b478..4568749d23 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -203,39 +203,11 @@ pg_tablespace_databases(PG_FUNCTION_ARGS)
 {
 	Oid			tablespaceOid = PG_GETARG_OID(0);
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	bool		randomAccess;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
 	char	   *location;
 	DIR		   *dirdesc;
 	struct dirent *de;
-	MemoryContext oldcontext;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_SYNTAX_ERROR),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
-	oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
-
-	tupdesc = CreateTemplateTupleDesc(1);
-	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "pg_tablespace_databases",
-					   OIDOID, -1, 0);
-
-	randomAccess = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
-	tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
-
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, SRF_SINGLE_USE_EXPECTED);
 
 	if (tablespaceOid == GLOBALTABLESPACE_OID)
 	{
@@ -291,7 +263,8 @@ pg_tablespace_databases(PG_FUNCTION_ARGS)
 		values[0] = ObjectIdGetDatum(datOid);
 		nulls[0] = false;
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+							 values, nulls);
 	}
 
 	FreeDir(dirdesc);
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index fd993d0d5f..eff45b16f2 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -461,25 +461,7 @@ pg_stat_get_progress_info(PG_FUNCTION_ARGS)
 	int			curr_backend;
 	char	   *cmd = text_to_cstring(PG_GETARG_TEXT_PP(0));
 	ProgressCommandType cmdtype;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
-
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
 
 	/* Translate command name into command type code. */
 	if (pg_strcasecmp(cmd, "VACUUM") == 0)
@@ -499,14 +481,7 @@ pg_stat_get_progress_info(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("invalid command name: \"%s\"", cmd)));
 
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	/* 1-based index */
 	for (curr_backend = 1; curr_backend <= num_backends; curr_backend++)
@@ -552,7 +527,7 @@ pg_stat_get_progress_info(PG_FUNCTION_ARGS)
 				nulls[i + 3] = true;
 		}
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 	}
 
 	return (Datum) 0;
@@ -569,34 +544,8 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 	int			curr_backend;
 	int			pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0);
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	/* 1-based index */
 	for (curr_backend = 1; curr_backend <= num_backends; curr_backend++)
@@ -629,7 +578,7 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 			nulls[5] = false;
 			values[5] = CStringGetTextDatum("<backend information not available>");
 
-			tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+			tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 			continue;
 		}
 
@@ -943,7 +892,7 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 			nulls[29] = true;
 		}
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 
 		/* If only a single backend was requested, and we found it, break. */
 		if (pid != -1)
@@ -1866,36 +1815,10 @@ pg_stat_get_slru(PG_FUNCTION_ARGS)
 {
 #define PG_STAT_GET_SLRU_COLS	9
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 	int			i;
 	PgStat_SLRUStats *stats;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	/* request SLRU stats from the stat collector */
 	stats = pgstat_fetch_slru();
@@ -1927,7 +1850,7 @@ pg_stat_get_slru(PG_FUNCTION_ARGS)
 		values[7] = Int64GetDatum(stat.truncate);
 		values[8] = TimestampTzGetDatum(stat.stat_reset_timestamp);
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 	}
 
 	return (Datum) 0;
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index b2003f5672..22ab5a4329 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -24,6 +24,7 @@
 #include "common/hashfn.h"
 #include "common/int.h"
 #include "common/unicode_norm.h"
+#include "funcapi.h"
 #include "lib/hyperloglog.h"
 #include "libpq/pqformat.h"
 #include "miscadmin.h"
@@ -4832,34 +4833,14 @@ text_to_table(PG_FUNCTION_ARGS)
 {
 	ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
 	SplitTextOutputData tstate;
-	MemoryContext old_cxt;
-
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsi == NULL || !IsA(rsi, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsi->allowedModes & SFRM_Materialize) ||
-		rsi->expectedDesc == NULL)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* OK, prepare tuplestore in per-query memory */
-	old_cxt = MemoryContextSwitchTo(rsi->econtext->ecxt_per_query_memory);
 
 	tstate.astate = NULL;
-	tstate.tupdesc = CreateTupleDescCopy(rsi->expectedDesc);
-	tstate.tupstore = tuplestore_begin_heap(true, false, work_mem);
-
-	MemoryContextSwitchTo(old_cxt);
+	SetSingleFuncCall(fcinfo, SRF_SINGLE_USE_EXPECTED);
+	tstate.tupstore = rsi->setResult;
+	tstate.tupdesc = rsi->setDesc;
 
 	(void) split_text(fcinfo, &tstate);
 
-	rsi->returnMode = SFRM_Materialize;
-	rsi->setResult = tstate.tupstore;
-	rsi->setDesc = tstate.tupdesc;
-
 	return (Datum) 0;
 }
 
diff --git a/src/backend/utils/fmgr/README b/src/backend/utils/fmgr/README
index 1e4c4b94a9..9d8848106d 100644
--- a/src/backend/utils/fmgr/README
+++ b/src/backend/utils/fmgr/README
@@ -305,6 +305,10 @@ If available, the expected tuple descriptor is passed in ReturnSetInfo;
 in other contexts the expectedDesc field will be NULL.  The function need
 not pay attention to expectedDesc, but it may be useful in special cases.
 
+SetSingleFuncCall() is a helper function able to setup the function's
+ReturnSetInfo for a single call, filling in the Tuplestore and the
+TupleDesc with the proper configuration for Materialize mode.
+
 There is no support for functions accepting sets; instead, the function will
 be called multiple times, once for each element of the input set.
 
diff --git a/src/backend/utils/fmgr/funcapi.c b/src/backend/utils/fmgr/funcapi.c
index 5d913ae08d..d269662ad8 100644
--- a/src/backend/utils/fmgr/funcapi.c
+++ b/src/backend/utils/fmgr/funcapi.c
@@ -19,6 +19,7 @@
 #include "catalog/pg_proc.h"
 #include "catalog/pg_type.h"
 #include "funcapi.h"
+#include "miscadmin.h"
 #include "nodes/nodeFuncs.h"
 #include "utils/array.h"
 #include "utils/builtins.h"
@@ -27,6 +28,7 @@
 #include "utils/regproc.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
+#include "utils/tuplestore.h"
 #include "utils/typcache.h"
 
 
@@ -54,6 +56,73 @@ static bool resolve_polymorphic_tupdesc(TupleDesc tupdesc,
 static TypeFuncClass get_type_func_class(Oid typid, Oid *base_typeid);
 
 
+/*
+ * SetSingleFuncCall
+ *
+ * Helper function to build the state of a set-returning function used
+ * in the context of a single call with materialize mode.  This code
+ * includes sanity checks on ReturnSetInfo, creates the Tuplestore and
+ * the TupleDesc used with the function and stores them into the
+ * function's ReturnSetInfo.
+ *
+ * "flags" can be set to SRF_SINGLE_USE_EXPECTED, to use the tuple
+ * descriptor coming from expectedDesc, which is the tuple descriptor
+ * expected by the caller.  SRF_SINGLE_BLESS can be set to complete the
+ * information associated to the tuple descriptor, which is necessary
+ * in some cases  where the tuple descriptor comes from a transient
+ * RECORD datatype.
+ */
+void
+SetSingleFuncCall(FunctionCallInfo fcinfo, bits32 flags)
+{
+	bool		random_access;
+	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	Tuplestorestate *tupstore;
+	MemoryContext old_context,
+				per_query_ctx;
+	TupleDesc	stored_tupdesc;
+
+	/* check to see if caller supports returning a tuplestore */
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize) ||
+		((flags & SRF_SINGLE_USE_EXPECTED) != 0 && rsinfo->expectedDesc == NULL))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	/*
+	 * Store the tuplestore and the tuple descriptor in ReturnSetInfo.  This
+	 * must be done in the per-query memory context.
+	 */
+	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
+	old_context = MemoryContextSwitchTo(per_query_ctx);
+
+	/* build a tuple descriptor for our result type */
+	if ((flags & SRF_SINGLE_USE_EXPECTED) != 0)
+		stored_tupdesc = CreateTupleDescCopy(rsinfo->expectedDesc);
+	else
+	{
+		if (get_call_result_type(fcinfo, NULL, &stored_tupdesc) != TYPEFUNC_COMPOSITE)
+			elog(ERROR, "return type must be a row type");
+	}
+
+	/* If requested, bless the tuple descriptor */
+	if ((flags & SRF_SINGLE_BLESS) != 0)
+		BlessTupleDesc(stored_tupdesc);
+
+	random_access = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
+
+	tupstore = tuplestore_begin_heap(random_access, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = stored_tupdesc;
+	MemoryContextSwitchTo(old_context);
+}
+
+
 /*
  * init_MultiFuncCall
  * Create an empty FuncCallContext data structure
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 1e3650184b..6d11f9c71b 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -10157,41 +10157,14 @@ show_all_file_settings(PG_FUNCTION_ARGS)
 {
 #define NUM_PG_FILE_SETTINGS_ATTS 7
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
 	ConfigVariable *conf;
 	int			seqno;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
-
-	/* Check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
 
 	/* Scan the config files using current context as workspace */
 	conf = ProcessConfigFileInternal(PGC_SIGHUP, false, DEBUG3);
 
-	/* Switch into long-lived context to construct returned data structures */
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
 	/* Build a tuplestore to return our results in */
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	/* The rest can be done in short-lived context */
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	/* Process the results and create a tuplestore */
 	for (seqno = 1; conf != NULL; conf = conf->next, seqno++)
@@ -10239,7 +10212,7 @@ show_all_file_settings(PG_FUNCTION_ARGS)
 			nulls[6] = true;
 
 		/* shove row into tuplestore */
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 	}
 
 	return (Datum) 0;
diff --git a/src/backend/utils/misc/pg_config.c b/src/backend/utils/misc/pg_config.c
index e646a41910..d9e18caf44 100644
--- a/src/backend/utils/misc/pg_config.c
+++ b/src/backend/utils/misc/pg_config.c
@@ -25,35 +25,12 @@ Datum
 pg_config(PG_FUNCTION_ARGS)
 {
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	Tuplestorestate *tupstore;
-	TupleDesc	tupdesc;
-	MemoryContext oldcontext;
 	ConfigData *configdata;
 	size_t		configdata_len;
 	int			i = 0;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	/* Build tuplestore to hold the result rows */
-	oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	/* initialize our tuplestore */
+	SetSingleFuncCall(fcinfo, 0);
 
 	configdata = get_configdata(my_exec_path, &configdata_len);
 	for (i = 0; i < configdata_len; i++)
@@ -67,7 +44,7 @@ pg_config(PG_FUNCTION_ARGS)
 		values[0] = CStringGetTextDatum(configdata[i].name);
 		values[1] = CStringGetTextDatum(configdata[i].setting);
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 	}
 
 	return (Datum) 0;
diff --git a/src/backend/utils/mmgr/portalmem.c b/src/backend/utils/mmgr/portalmem.c
index afc03682d9..d549f66d4a 100644
--- a/src/backend/utils/mmgr/portalmem.c
+++ b/src/backend/utils/mmgr/portalmem.c
@@ -1132,43 +1132,14 @@ Datum
 pg_cursor(PG_FUNCTION_ARGS)
 {
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 	HASH_SEQ_STATUS hash_seq;
 	PortalHashEnt *hentry;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* need to build tuplestore in query context */
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
 	/*
 	 * We put all the tuples into a tuplestore in one scan of the hashtable.
 	 * This avoids any issue of the hashtable possibly changing between calls.
 	 */
-	tupstore =
-		tuplestore_begin_heap(rsinfo->allowedModes & SFRM_Materialize_Random,
-							  false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	/* generate junk in short-term context */
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	hash_seq_init(&hash_seq, PortalHashTable);
 	while ((hentry = hash_seq_search(&hash_seq)) != NULL)
@@ -1190,13 +1161,9 @@ pg_cursor(PG_FUNCTION_ARGS)
 		values[4] = BoolGetDatum(portal->cursorOptions & CURSOR_OPT_SCROLL);
 		values[5] = TimestampTzGetDatum(portal->creation_time);
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 	}
 
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
 	return (Datum) 0;
 }
 
diff --git a/src/include/funcapi.h b/src/include/funcapi.h
index ba927c2f33..dc3d819a1c 100644
--- a/src/include/funcapi.h
+++ b/src/include/funcapi.h
@@ -278,14 +278,20 @@ extern Datum HeapTupleHeaderGetDatum(HeapTupleHeader tuple);
  * memory allocated in multi_call_memory_ctx, but holding file descriptors or
  * other non-memory resources open across calls is a bug.  SRFs that need
  * such resources should not use these macros, but instead populate a
- * tuplestore during a single call, and return that using SFRM_Materialize
- * mode (see fmgr/README).  Alternatively, set up a callback to release
- * resources at query shutdown, using RegisterExprContextCallback().
+ * tuplestore during a single call, as set up by SetSingleFuncCall() (see
+ * fmgr/README).  Alternatively, set up a callback to release resources
+ * at query shutdown, using RegisterExprContextCallback().
  *
  *----------
  */
 
 /* from funcapi.c */
+
+/* flag bits for SetSingleFuncCall() */
+#define SRF_SINGLE_USE_EXPECTED	0x01	/* use expectedDesc as tupdesc */
+#define SRF_SINGLE_BLESS		0x02	/* validate tuple for SRF */
+extern void SetSingleFuncCall(FunctionCallInfo fcinfo, bits32 flags);
+
 extern FuncCallContext *init_MultiFuncCall(PG_FUNCTION_ARGS);
 extern FuncCallContext *per_MultiFuncCall(PG_FUNCTION_ARGS);
 extern void end_MultiFuncCall(PG_FUNCTION_ARGS, FuncCallContext *funcctx);