The userInfo parameter of the userNotification method is a value of
Notifications containing binary and string (Binary, String, StringUtf8) data of up to 48K bytes can be sent across the network. For applications running within the server node, the limit for notifications containing binary or string data is 2G bytes. Note, however, that this applies only to single user and server applications. In multiuser applications, persistent notifications are sent via the database server, even if the receiving process is on the same node as the sender. In notification cause events, exception 1267 (Notification info object too big) is raised if the binary of string userInfo data exceeds the applicable value.