Allow only one session per registered user

Question

Hi,
we plan to implement a security module in our application that will display at login time if the user has other sessions still open and to give him the possibility to proceed and then to automatically purge all the other sessions he has, or to stop as maybe he has the other session just in another browser / another computer.
The APEX_WORKSPACE_SESSIONS view shows very useful information in this matter, but beside the fields in it, it would be very useful to have also the last access/activity time for that session. How is best to get this? Join with the APEX_WORKSPACE_ACTIVITY_LOG view like this?
SELECT q1.apex_session_id, q1.user_name, q1.session_created, q2.application_id, q2.first_access, q2.last_access, q2.requests
FROM
  (SELECT * FROM APEX_WORKSPACE_SESSIONS WHERE user_name != 'nobody') q1,
  (SELECT apex_session_id, application_id, MAX(view_date) last_access, MIN(view_date) first_access, count(*) requests
      FROM APEX_WORKSPACE_ACTIVITY_LOG
      WHERE apex_user != 'nobody'
      GROUP BY apex_session_id, application_id
  ) q2
WHERE q1.apex_session_id =q2.apex_session_id
ORDER BY 3 DESC;And now my second question: Is it possible to purge the previous sessions, when the user accept this option? For example the sessions that remained open, when the user just closed the browser, or IE/Windows crashed :). How can this be done?(not the IE/Windows crash as that is simple :) ) Or at least to invalidate all objects in those sessions.
Thanks in advance,
Florin

Answer 1

I have an SR opened with Oracle support and here is what they say:
It looks like we are hitting
Bug 7587013 - INSERTING AND DELETING WWV_FLOW_DATA CAUSES DEADLOCK, which is also related to
Bug 6618662 - APEX APPEARS TO BE CAUSING DEADLOCK - CASE COLLECTION.
To further clarify the issue, these DML statements from the APEX engine are used when rendering classic reports (and in the computation of the pagination set).
There is no fix yet for the issue, however the frequency of the issue decreases dramatically in the last version (which you currently have).
The issue should be fixed in Apex release 4.1
It appears that the only way this deadlock can occur is if two requests for the same APEX session are made concurrently.
This can be due to a user getting impatient and hitting their refresh button in their browser, or a user opening up a new tab in their browser and concurrently running the same page with the same report.
Not really helpful IMHO, suggesting to wait for a version that will not be release soon :(. If any of the APEX team engineers / PM is interested I can dig deeper into the issue and isolate the whole chain of requests from an user that hits this error, which unfortunately appears more and more often lately :(. I need to find at least an workaround if not a fix as now I get daily at least 7 such ORA-60 Deadlock detected issues.
Just last week I was able to produce a nice testcase for a bug in APEX_MAIL, and prod dev made the patch in less than a day, with all the timezone difference issues. I was pretty impressed when getting that quick the patch 9414444 (thanks Joel :) ).
Florin