

If # Shrink is low:
    If AvShr is low:
        If Avgsz Activ is much smaller than Opt Mb:
            Reduce OPTIMAL (since not many shrinks occur).
    If AvShr is high:
        Good value for OPTIMAL.
If # Shrink is high:
    If AvShr is low:
        Too many shrinks being performed,since OPTIMAL is
        somewhat (but not hugely) too small.
    If AvShr is high:
        Increase OPTIMAL until # of Shrnk decreases.  Periodic
        long transactions are probably causing this.

A high value in the #Ext column indicates dynamic extension,in which case
you should consider increasing your rollback segment size.  (Also,increase
it if you get a "Shapshot too old" error).  A high value in the # Extend
and # Shrink columns indicate allocation and deallocation of extents, due
to rollback segments with a smaller optimal size.  It also may be due to
a batch processing transaction assigned to a smaller rollback segment.
Consider increasing OPTIMAL.


