diff --git a/postgresql-8.4.13/src/backend/utils/misc/guc.c b/postgresql-8.4.13/src/backend/utils/misc/guc.c
index 0ceb89f..03f4f79 100644
--- a/postgresql-8.4.13/src/backend/utils/misc/guc.c
+++ b/postgresql-8.4.13/src/backend/utils/misc/guc.c
@@ -2421,7 +2421,7 @@ static struct config_string ConfigureNamesString[] =
 			GUC_SUPERUSER_ONLY
 		},
 		&UnixSocketDir,
-		"", assign_canonical_path, NULL
+		"/var/run/postgresql/", assign_canonical_path, NULL
 	},
 
 	{