The coupling facility list structure version number returned for coupling facility log streams is helpful in situations where a rebuild occurs while the resource manager responsible for gathering data for a log stream was inactive at the time of the rebuild. A browsing application can tell if a rebuild has occurred since it was last connected by checking to see if the coupling facility list structure version number has increased since the last browse session. If a browsing application connects to a log stream and issues IXGQUERY to find that the version number has increased, it should then begin browsing from the last valid safe import point it knew about for the most up to date version of the log stream contents.
For example, imagine an application browses log blocks 1 through 6 in a source log stream in anticipation of importing them. Before importing the log blocks to the target log stream, the application checks for the safe import point using IXGQUERY and imports only blocks 1 and 2. Then, the browsing application is cancelled or fails and disconnects from the log stream, saving the current coupling facility list structure version number and safe import point it knows about (2).
A rebuild then occurs and the new content of the source log stream consists of 1, 2, 4, 5, and 6. The browsing application then reconnects to the log stream and issues IXGQUERY for the new list structure version number and safe import point. Since a rebuild has occurred, the version number will have increased. The browsing application begins browsing again from the last safe import point (2) to the new safe import point (6), and only imports log blocks 4, 5, and 6.