Channel Hub is not cluster aware so notifications are lost between nodes

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.1.X EE, 6.2.X EE, 7.0.0 M3
• Fix Version/s: 6.1.X EE, 6.2.2 CE GA3 , 6.2.3 CE GA4, 6.2.X EE, 7.0.0 M2
• Component/s: Collaboration, User Notifications
• Labels:
  • 6.1_release_notes
  • liferay-fixpack-platform-28-6130
  • liferay-fixpack-platform-30-6210
  • liferay-fixpack-platform-37-6210
• Branch Version/s:
  6.2.x, 6.1.x
• Backported to Branch:
  Committed
• Fix Priority: 3
• Git Pull Request: https://github.com/shuyangzhou/liferay-portal/pull/709

Channel hub is only implemented in SO 2.x in 6.1.x so this will not be testable in master and 6.2 but the issue is still present in the code.

short description of the client's issue:
Within a SO cluster, the dock bar is not correctly displaying that users have notifications.
Steps to reproduce / testing done:
1. Create a clustered SO environment with 2 nodes using the default cluster configuration.
cluster.link.enabled=true
ehcache.cluster.link.replication.enabled=true
lucene.replicate.write=true
2. Create two users 'user1' and 'user2' give both users the role 'Social Office User'
3. On a SO site, add the Contact Portlet.
4. Login as user1 in node1 and user2 in node2.
5. As user1, Send a Connection request or a Private Message to user2.
Results of steps / testing:
Expected Result: After refreshing the page, Dockbar will display that there is a pending notification for user2.
Actual Result: Refreshing the page, no notifications are pending within the Dockbar. The user is able to see the notification when clicking the 'View All' as well as logging out and logging back in.
The notifications should act like all of our portlets within a cluster in which changes that occur within the cluster should be presented immediately.
Tested in:
Issue REPRODUCED
branch 6.1.x - 544b23baf553126350dd21b5b4dd1fa6a36c83e7
6.1.x plugins - 6ad6cc20cd0b6716f290bea0810095b6a70a1a7f

see SOS-2404