Caching unavailable views

Understand the concept of cache in clearmake and cleartool sessions.

When clearmake shops for a derived object to wink in to a build, it might find DOs from a view that is unavailable (because the view server host is down, the albd_server is not running on the server host, and so on). Attempting to fetch the configuration record of a DO from an unavailable view causes a long time-out, and the build might reference multiple DOs from the same view.

clearmake and other cleartool commands that access configuration records and DOs (lsdo, describe, catcr, diffcr) maintain a cache of tags of inaccessible views. For each view tag, the command records the time of the first unsuccessful contact. Before trying to access a view, the command checks the cache. If the view's tag is not listed in the cache, the command tries to contact the view. If the view's tag is listed in the cache, the command compares the time elapsed since the last attempt with the time-out period specified by the CCASE_DNVW_RETRY environment variable. If the elapsed time is greater than the time-out period, the command removes the view tag from the cache and tries to contact the view again.

Note: The cache is not persistent across clearmake sessions. Each recursive or individual invocation of clearmake attempts to contact a view whose tag might have been cached in a previous invocation.

The default time-out period is 60 minutes. To specify a different time-out period, set CCASE_DNVW_RETRY to another integer value (representing minutes). To disable the cache, set CCASE_DNVW_RETRY to 0.