Question: 

When you see the following messages in the tracelog, what does it mean:

"Messages for client subscription may be stuck! Backlog messages=<some number>"

Answer: 

This message means that there is a client connection which is not accepting any messages since last 10 minutes. So, it is closing that connection from Server side. These messages are part of status message subscription or the workload subscription and it has exceeded the threshold.

In order to avoid lot of memory consumption when huge data is subscribed to a client, Desktop Client maintains the following thresholds to determine whether it can process the data or terminate the subscription.

• The messages are above 1000 (by default) and
• The timeout till last time data is subscribed (by default 10 minutes)

If both are satisfied, the Desktop Client will log the message and terminate the subscription, so no messages are not getting stuck.

The parameters are configurable from Desktop Client;

1. Admin perspective -> Topology
2. Right click on server instance and select "Configure Instance Parameters"
3. Click on "Internal" and click "button" next to it.

It will show a list of parameters including;

*Maximum number of backlogged messages for a subscriber (By default 1000)
*Read timeout threshold in minute above which a subscriber is terminated (By default 10)

Important Note:  Please consult CA Support before changing the value of these parameters.