System Resource Usage Troubleshooting

Setup

All Versions

These guidelines provide some ideas on using ObjecTime in such a way as to avoid potential problems with the interaction between ObjecTime and the environment it executes in.

• Keep a low number of updates in you session. This keeps your image size down, both in memory and on disk. An update on disk of about 2M is about 7-8M in memory.
   
• Errors in ObjecTime, such as:
  
  • exceptions (in ObjecTimeSystemExceptions) of a "a primitive has failed",
  • in some instances, a startup dialog stating the session can't be saved may indicate memory shortage on either the host where ObjecTime is executing or on the X terminal where the session is displayed. Try to exit out of applications as appropriate in order to free up memory resources. (You may have to have other users do this as well.)
   
  The above symptoms indicating memory shortage, may appear after performing some memory intensive operations. Memory intensive operations include:
  
  • merging large classes
  • activation of large updates
  • passivation of large updates
  • reset of RTS when large trace thresholds defined
   
  Note that, although these operations require extra memory during execution, the memory becomes available for use by other operations on completion of execution. Memory allocated by ObjecTime is not returned to the operating system while a session is active -- it is held and reused in subsequent processing.
   
  If memory shortage is suspected, then here is a procedure that can be used with respect to ObjecTime that may allow reclamation of memory:
  • first, save your session, exit, and then restart. If this doesn't reclaim enough memory, then:
  • passivate your update(s)
  • exit your session (after saving it, if necessary)
  • move your current (saved) image to another file as a temporary backup
  • obtain a new image
  • start your new session and activate the required update(s)
  • (For large trace thresholds, also consider decreasing the threshold value.)
   
• Although activation and passivation some times take a long time and may also cause recompilation, it is suggested that you passivate changed updates once a day, and create a new image once a week.
   
• Use of precompiled packages can minimize the number and size of model entities in a session.
   
• If possible, save and passivate to a local disk -- this will be faster than across an NFS mount.