With Microsoft Dynamics Nav, there are various ways of viewing all the active sessions within the system. The easiest of which is the “Sessions” page within the software itself:
The downside of this, is that it only shows active sessions on the tier which the user is connected. This is ok for solutions where the system has a single tier, however it is common to have multiple tiers in order to spread load. Checking this way is time consuming as you need to check multiple tiers in order to get a session count.
However using SQL can be an easy way to get the number of active sessions:
SELECT [User ID] ,[Server Instance Name] ,[Server Computer Name] ,[Database Name] ,[Client Computer Name] ,[Login Datetime] FROM [dbo].[Active Session]
It is worth nothing that Nav tidies up this table automatically, but in some cases it may be incorrect. For example if a middle tier crashes out, it could be left with orphaned records until the tier starts up again (or another tier prunes the records down).