WebSphere Application Server V7.0: Concepts ... - IBM Redbooks

The results of this can be as follows:
► Thread can be freed
If this is the case, then the user whose request hung receives an exception.
The administrator can define what dump-action should be taken (none,
svcdump, javacore, or traceback).
► Thread cannot be freed
In the case that a thread cannot be freed, the system action depends on the
administrator settings. The options are as follows:
– Abend the servant
– Keep the servant up and running
– Take a dump (defined by new variables)
See Table 14-2 on page 455.
Although the basic options if a thread cannot be freed are still the same as in
prior versions of the WebSphere Application Server for z/OS product, the
decision whether a servant should be abended or kept alive now depends on the
following factors:
► How much CPU time is consumed by the thread? (Looping or just hanging?)
► Is the servant the last servant?
► How many threads are already in a hung state, within this servant?
14.7.4 New properties
Note: The code that is used to unblock a thread is provided by the WebSphere
Application Server V7.0. To use the Thread Hang Recovery for your
application serving environment, you do not have to implement code for the
Interruptable Objects registry.
For more details on the corresponding parameters, refer to 14.7.4, “New
properties” on page 454.
If a thread that was reported to the controller as hung finishes, the controller is
notified of that so that it is no longer considered in the threshold determination.
As described in the previous section, WebSphere Application Server V7.0
introduces a set of new variables that allow the administrator to configure the
behavior of the application server if a hung thread cannot be freed.
454 WebSphere Application Server V7.0: Concepts, Planning, and Design