It's really, really important to understand that there is no such thing as an
"unused version". Versions, by themselves, are not very important -- all they do
is provide a name to a state. But applying that name to a state other than 0
will prevent the state tree from being pruned -- just having a version means the
state is in use. ArcGIS uses the list of versions to determine how to compress
the state tree. Any version has the potential to prevent compression, not just
old ones (though older versions are more likely to point to older states).
The geodatabase administrator needs to actively monitor the state tree, to make
sure optimal compression is occurring on a regular basis. It's unlikely there could
be a fully automated process to review whether versions are "stale" (and should be
deleted) without a significant risk of deleting versions which are important.
- V
