diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index fa3c8a7905..bf1fbca532 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3253,7 +3253,7 @@ static struct config_real ConfigureNamesReal[] =
 			NULL
 		},
 		&vacuum_cleanup_index_scale_factor,
-		0.1, 0.0, 100.0,
+		0.1, 0.0, DBL_MAX,
 		NULL, NULL, NULL
 	},