How to find out how many users are working in Process Portal at the given time?

I can answer this question but my way won't absolutely precise.


You can find out the number of working users using this SQL-query (for Oracle): 

SELECT COUNT(DISTINCT BPMDBAPC.LSW_USR_XREF.FULL_NAME) as USERS_NUM
FROM BPMDBAPC.LSW_TASK
INNER JOIN BPMDBAPC.LSW_USR_XREF
ON BPMDBAPC.LSW_TASK.USER_ID = BPMDBAPC.LSW_USR_XREF.USER_ID
INNER JOIN BPMDBAPC.LSW_BPD_INSTANCE
ON BPMDBAPC.LSW_TASK.BPD_INSTANCE_ID = BPMDBAPC.LSW_BPD_INSTANCE.BPD_INSTANCE_ID
WHERE BPMDBAPC.LSW_BPD_INSTANCE.LAST_MODIFIED_DATETIME >= SysDate - (30 / 1440);


USERS_NUM
----------
         2

And this query shows the list of these users:

SELECT BPMDBAPC.LSW_USR_XREF.FULL_NAME
FROM BPMDBAPC.LSW_TASK
INNER JOIN BPMDBAPC.LSW_USR_XREF
ON BPMDBAPC.LSW_TASK.USER_ID = BPMDBAPC.LSW_USR_XREF.USER_ID
INNER JOIN BPMDBAPC.LSW_BPD_INSTANCE
ON BPMDBAPC.LSW_TASK.BPD_INSTANCE_ID = BPMDBAPC.LSW_BPD_INSTANCE.BPD_INSTANCE_ID
WHERE BPMDBAPC.LSW_BPD_INSTANCE.LAST_MODIFIED_DATETIME >= SysDate - (30 / 1440)
GROUP BY BPMDBAPC.LSW_USR_XREF.FULL_NAME;

FULL_NAME                                                                                                                                                                                                                                                    
----------------
bpmadmin
wasadmin                                                                                                                                                                          

I can explain my mind:

During work instances of BPM process are changed constantly. We can find the time of change and the users what change the instances. By default, session timeout in BPM = 30 minutes.
So if we find the list of the users which changed instances last 30 minutes - we can find (with a certain degree of probability) the numbers of users connected to Process Portal.