diff --git a/src/backend/utils/fmgr/fmgr.c b/src/backend/utils/fmgr/fmgr.c
index 9208c31fe06..6b2d7d7be38 100644
--- a/src/backend/utils/fmgr/fmgr.c
+++ b/src/backend/utils/fmgr/fmgr.c
@@ -612,7 +612,8 @@ struct fmgr_security_definer_cache
 {
 	FmgrInfo	flinfo;			/* lookup info for target function */
 	Oid			userid;			/* userid to set, or InvalidOid */
-	ArrayType  *proconfig;		/* GUC values to set, or NULL */
+	List	   *configNames;	/* GUC names to set, or NIL */
+	List	   *configValues;	/* GUC values to set, or NIL */
 	Datum		arg;			/* passthrough argument for plugin modules */
 };
 
@@ -634,6 +635,8 @@ fmgr_security_definer(PG_FUNCTION_ARGS)
 	FmgrInfo   *save_flinfo;
 	Oid			save_userid;
 	int			save_sec_context;
+	ListCell   *lc1;
+	ListCell   *lc2;
 	volatile int save_nestlevel;
 	PgStat_FunctionCallUsage fcusage;
 
@@ -666,8 +669,11 @@ fmgr_security_definer(PG_FUNCTION_ARGS)
 								&isnull);
 		if (!isnull)
 		{
+			ArrayType *array;
 			oldcxt = MemoryContextSwitchTo(fcinfo->flinfo->fn_mcxt);
-			fcache->proconfig = DatumGetArrayTypePCopy(datum);
+			array = DatumGetArrayTypeP(datum);
+			TransformGUCArray(array, &fcache->configNames,
+							  &fcache->configValues);
 			MemoryContextSwitchTo(oldcxt);
 		}
 
@@ -680,7 +686,7 @@ fmgr_security_definer(PG_FUNCTION_ARGS)
 
 	/* GetUserIdAndSecContext is cheap enough that no harm in a wasted call */
 	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	if (fcache->proconfig)		/* Need a new GUC nesting level */
+	if (fcache->configNames != NIL)		/* Need a new GUC nesting level */
 		save_nestlevel = NewGUCNestLevel();
 	else
 		save_nestlevel = 0;		/* keep compiler quiet */
@@ -689,12 +695,17 @@ fmgr_security_definer(PG_FUNCTION_ARGS)
 		SetUserIdAndSecContext(fcache->userid,
 							   save_sec_context | SECURITY_LOCAL_USERID_CHANGE);
 
-	if (fcache->proconfig)
+	forboth(lc1, fcache->configNames, lc2, fcache->configValues)
 	{
-		ProcessGUCArray(fcache->proconfig,
-						(superuser() ? PGC_SUSET : PGC_USERSET),
-						PGC_S_SESSION,
-						GUC_ACTION_SAVE);
+		GucContext	 context = superuser() ? PGC_SUSET : PGC_USERSET;
+		GucSource	 source	 = PGC_S_SESSION;
+		GucAction	 action	 = GUC_ACTION_SAVE;
+		char		*name	 = lfirst(lc1);
+		char		*value	 = lfirst(lc2);
+
+		(void) set_config_option(name, value,
+								 context, source,
+								 action, true, 0, false);
 	}
 
 	/* function manager hook */
@@ -737,7 +748,7 @@ fmgr_security_definer(PG_FUNCTION_ARGS)
 
 	fcinfo->flinfo = save_flinfo;
 
-	if (fcache->proconfig)
+	if (fcache->configNames != NIL)
 		AtEOXact_GUC(true, save_nestlevel);
 	if (OidIsValid(fcache->userid))
 		SetUserIdAndSecContext(save_userid, save_sec_context);
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 5308896c87f..3449470953a 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -6215,14 +6215,12 @@ ParseLongOption(const char *string, char **name, char **value)
 
 
 /*
- * Handle options fetched from pg_db_role_setting.setconfig,
- * pg_proc.proconfig, etc.  Caller must specify proper context/source/action.
- *
- * The array parameter must be an array of TEXT (it must not be NULL).
+ * Transform array of GUC settings into lists of names and values. The lists
+ * are faster to process in cases where the settings must be applied
+ * repeatedly (e.g. for each function invocation).
  */
 void
-ProcessGUCArray(ArrayType *array,
-				GucContext context, GucSource source, GucAction action)
+TransformGUCArray(ArrayType *array, List **names, List **values)
 {
 	int			i;
 
@@ -6231,6 +6229,8 @@ ProcessGUCArray(ArrayType *array,
 	Assert(ARR_NDIM(array) == 1);
 	Assert(ARR_LBOUND(array)[0] == 1);
 
+	*names = NIL;
+	*values = NIL;
 	for (i = 1; i <= ARR_DIMS(array)[0]; i++)
 	{
 		Datum		d;
@@ -6262,14 +6262,45 @@ ProcessGUCArray(ArrayType *array,
 			continue;
 		}
 
+		*names = lappend(*names, name);
+		*values = lappend(*values, value);
+
+		pfree(s);
+	}
+}
+
+
+/*
+ * Handle options fetched from pg_db_role_setting.setconfig,
+ * pg_proc.proconfig, etc.  Caller must specify proper context/source/action.
+ *
+ * The array parameter must be an array of TEXT (it must not be NULL).
+ */
+void
+ProcessGUCArray(ArrayType *array,
+				GucContext context, GucSource source, GucAction action)
+{
+	List *gucNames;
+	List *gucValues;
+	ListCell *lc1;
+	ListCell *lc2;
+
+	TransformGUCArray(array, &gucNames, &gucValues);
+	forboth(lc1, gucNames, lc2, gucValues)
+	{
+		char *name = lfirst(lc1);
+		char *value = lfirst(lc2);
+
 		(void) set_config_option(name, value,
 								 context, source,
 								 action, true, 0, false);
 
 		pfree(name);
 		pfree(value);
-		pfree(s);
 	}
+
+	list_free(gucNames);
+	list_free(gucValues);
 }
 
 
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index 223a19f80d8..e89083ee0e6 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -391,6 +391,8 @@ extern void AlterSystemSetConfigFile(AlterSystemStmt *altersysstmt);
 extern char *GetConfigOptionByName(const char *name, const char **varname,
 								   bool missing_ok);
 
+extern void TransformGUCArray(ArrayType *array, List **configNames,
+							  List **configValues);
 extern void ProcessGUCArray(ArrayType *array,
 							GucContext context, GucSource source, GucAction action);
 extern ArrayType *GUCArrayAdd(ArrayType *array, const char *name, const char *value);