Automatically periodically reindex repositories, particularly with Perforce

I don't know if this applies to other SCM systems, but it definitely applies to Perforce.

In Perforce, there are three operations that you can do which will "change history" (which otherwise can't be done):
1) Obliterating files
2) Changing submitted changelist descriptions
3) Assigning a job to a submitted changelist

All three are pretty common in Perforce (well, #2 less so than the others), and lead to FishEye reporting different results than other tools, because FishEye never rescans things that it's already scanned.

The only current solution to this is to perform a reindex, which for us takes many many hours (our main p4 repository has >145k changelists). Therefore, the only time that we can realistically do it is over a weekend, which means that someone in the latest time zone has to remember to kick it off Friday night just before they leave. That isn't ideal.

We'd much prefer to be able to automatically schedule a weekly reindex so that any changes in terms of obliteration or retrospective changes to perforce history are picked up at least once a week.