diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index f15c97ad7a..51fac77f3d 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -2854,7 +2854,7 @@ postgresExplainForeignScan(ForeignScanState *node, ExplainState *es)
 				{
 					char	   *namespace;
 
-					namespace = get_namespace_name(get_rel_namespace(rte->relid));
+					namespace = get_namespace_name_or_temp(get_rel_namespace(rte->relid));
 					appendStringInfo(relations, "%s.%s",
 									 quote_identifier(namespace),
 									 quote_identifier(relname));
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 340db2bac4..36fbe129cf 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -3747,7 +3747,7 @@ ExplainTargetRel(Plan *plan, Index rti, ExplainState *es)
 			Assert(rte->rtekind == RTE_RELATION);
 			objectname = get_rel_name(rte->relid);
 			if (es->verbose)
-				namespace = get_namespace_name(get_rel_namespace(rte->relid));
+				namespace = get_namespace_name_or_temp(get_rel_namespace(rte->relid));
 			objecttag = "Relation Name";
 			break;
 		case T_FunctionScan:
@@ -3774,8 +3774,7 @@ ExplainTargetRel(Plan *plan, Index rti, ExplainState *es)
 
 						objectname = get_func_name(funcid);
 						if (es->verbose)
-							namespace =
-								get_namespace_name(get_func_namespace(funcid));
+							namespace = get_namespace_name_or_temp(get_func_namespace(funcid));
 					}
 				}
 				objecttag = "Function Name";
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 5e7108f903..4df8cc5abf 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -1617,7 +1617,7 @@ pg_get_statisticsobj_worker(Oid statextid, bool columns_only, bool missing_ok)
 
 	if (!columns_only)
 	{
-		nsp = get_namespace_name(statextrec->stxnamespace);
+		nsp = get_namespace_name_or_temp(statextrec->stxnamespace);
 		appendStringInfo(&buf, "CREATE STATISTICS %s",
 						 quote_qualified_identifier(nsp,
 													NameStr(statextrec->stxname)));
@@ -2811,7 +2811,7 @@ pg_get_functiondef(PG_FUNCTION_ARGS)
 	 * We always qualify the function name, to ensure the right function gets
 	 * replaced.
 	 */
-	nsp = get_namespace_name(proc->pronamespace);
+	nsp = get_namespace_name_or_temp(proc->pronamespace);
 	appendStringInfo(&buf, "CREATE OR REPLACE %s %s(",
 					 isfunction ? "FUNCTION" : "PROCEDURE",
 					 quote_qualified_identifier(nsp, name));
@@ -11183,7 +11183,7 @@ get_opclass_name(Oid opclass, Oid actual_datatype,
 			appendStringInfo(buf, " %s", quote_identifier(opcname));
 		else
 		{
-			nspname = get_namespace_name(opcrec->opcnamespace);
+			nspname = get_namespace_name_or_temp(opcrec->opcnamespace);
 			appendStringInfo(buf, " %s.%s",
 							 quote_identifier(nspname),
 							 quote_identifier(opcname));
@@ -11495,7 +11495,7 @@ generate_relation_name(Oid relid, List *namespaces)
 		need_qual = !RelationIsVisible(relid);
 
 	if (need_qual)
-		nspname = get_namespace_name(reltup->relnamespace);
+		nspname = get_namespace_name_or_temp(reltup->relnamespace);
 	else
 		nspname = NULL;
 
@@ -11527,7 +11527,7 @@ generate_qualified_relation_name(Oid relid)
 	reltup = (Form_pg_class) GETSTRUCT(tp);
 	relname = NameStr(reltup->relname);
 
-	nspname = get_namespace_name(reltup->relnamespace);
+	nspname = get_namespace_name_or_temp(reltup->relnamespace);
 	if (!nspname)
 		elog(ERROR, "cache lookup failed for namespace %u",
 			 reltup->relnamespace);
@@ -11639,7 +11639,7 @@ generate_function_name(Oid funcid, int nargs, List *argnames, Oid *argtypes,
 		p_funcid == funcid)
 		nspname = NULL;
 	else
-		nspname = get_namespace_name(procform->pronamespace);
+		nspname = get_namespace_name_or_temp(procform->pronamespace);
 
 	result = quote_qualified_identifier(nspname, proname);
 
@@ -11702,7 +11702,7 @@ generate_operator_name(Oid operid, Oid arg1, Oid arg2)
 		nspname = NULL;
 	else
 	{
-		nspname = get_namespace_name(operform->oprnamespace);
+		nspname = get_namespace_name_or_temp(operform->oprnamespace);
 		appendStringInfo(&buf, "OPERATOR(%s.", quote_identifier(nspname));
 	}
 
@@ -11790,7 +11790,7 @@ add_cast_to(StringInfo buf, Oid typid)
 	typform = (Form_pg_type) GETSTRUCT(typetup);
 
 	typname = NameStr(typform->typname);
-	nspname = get_namespace_name(typform->typnamespace);
+	nspname = get_namespace_name_or_temp(typform->typnamespace);
 
 	appendStringInfo(buf, "::%s.%s",
 					 quote_identifier(nspname), quote_identifier(typname));
@@ -11822,7 +11822,7 @@ generate_qualified_type_name(Oid typid)
 	typtup = (Form_pg_type) GETSTRUCT(tp);
 	typname = NameStr(typtup->typname);
 
-	nspname = get_namespace_name(typtup->typnamespace);
+	nspname = get_namespace_name_or_temp(typtup->typnamespace);
 	if (!nspname)
 		elog(ERROR, "cache lookup failed for namespace %u",
 			 typtup->typnamespace);
@@ -11856,7 +11856,7 @@ generate_collation_name(Oid collid)
 	collname = NameStr(colltup->collname);
 
 	if (!CollationIsVisible(collid))
-		nspname = get_namespace_name(colltup->collnamespace);
+		nspname = get_namespace_name_or_temp(colltup->collnamespace);
 	else
 		nspname = NULL;
 
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 6bba5f8ec4..4ebaa552a2 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -3340,7 +3340,7 @@ char *
 get_namespace_name_or_temp(Oid nspid)
 {
 	if (isTempNamespace(nspid))
-		return "pg_temp";
+		return pstrdup("pg_temp");
 	else
 		return get_namespace_name(nspid);
 }
diff --git a/src/test/regress/expected/explain.out b/src/test/regress/expected/explain.out
index cda28098ba..16e196a7bd 100644
--- a/src/test/regress/expected/explain.out
+++ b/src/test/regress/expected/explain.out
@@ -477,6 +477,19 @@ select jsonb_pretty(
 (1 row)
 
 rollback;
+-- Test display of temporary objects
+create temp table t1(f1 float8);
+create function pg_temp.mysin(float8) returns float8 language plpgsql
+as 'begin return sin($1); end';
+select explain_filter('explain (verbose) select * from t1 where pg_temp.mysin(f1) < 0.5');
+                       explain_filter                       
+------------------------------------------------------------
+ Seq Scan on pg_temp.t1  (cost=N.N..N.N rows=N width=N)
+   Output: f1
+   Filter: (pg_temp.mysin(t1.f1) < 'N.N'::double precision)
+(3 rows)
+
+-- Test compute_query_id
 set compute_query_id = on;
 select explain_filter('explain (verbose) select * from int8_tbl i8');
                          explain_filter                         
diff --git a/src/test/regress/sql/explain.sql b/src/test/regress/sql/explain.sql
index 3f9ae9843a..f401d99409 100644
--- a/src/test/regress/sql/explain.sql
+++ b/src/test/regress/sql/explain.sql
@@ -104,5 +104,14 @@ select jsonb_pretty(
 
 rollback;
 
+-- Test display of temporary objects
+create temp table t1(f1 float8);
+
+create function pg_temp.mysin(float8) returns float8 language plpgsql
+as 'begin return sin($1); end';
+
+select explain_filter('explain (verbose) select * from t1 where pg_temp.mysin(f1) < 0.5');
+
+-- Test compute_query_id
 set compute_query_id = on;
 select explain_filter('explain (verbose) select * from int8_tbl i8');