Login triggers are different from ordinary stored procedures in that once they are registered they execute in the background, without active user connections. Once you have configured a login trigger, Adaptive Server automatically executes it in the background as soon as the user logs in, but before the server executes any commands from the client application.
If one login makes multiple concurrent connections, the login trigger executes independently during each session. Similarly, multiple logins can configure the same stored procedure to be a login trigger.
Background execution means that you cannot use some standard features of stored procedures in a stored procedure configured as a login trigger. For instance, you cannot pass any parameters without default values to or from the procedure, nor will the procedure pass back any result values.
This special execution mode affects any stored procedures that are called by the login trigger stored procedure, as well as any output generated by the login trigger stored procedure itself.
You can also execute a login trigger stored procedure as a normal stored procedure, for example, from isql. The procedure executes and behaves normally, showing all output and error messages as usual.
