We've got hudson running against one replica of a multi-site setup. It's building a stream that is only
changed on the master. The master syncs with the replica every 15 minutes. Hudson seems to miss
changes in certain situations.

Hudson polls for changes since the last time it polled, and I think that is the problem. The clearcase
syncing process can make changes appear on a slave in the past. For example:

clearcase syncs at 0100 all changes from the master are copied to the replica.

hudson polls the replica at 0103 and builds, finishing at 0105

a change is made on the master at 0107

hudson polls the replica at 0113 for changes since 0103, no changes yet.

clearcase syncs at 0115, the change from 0107 is now available in the replica

hudson polls the replica at 0123 for changes since 0113, no changes

Notice how the change at 0107 gets lost and not built on the replica.

One fix for this behavior is to poll for changes since the last change seen, rather than since the last poll
time.