rep-cache.db: was SVN repo

[Stephen Montgomery-Smith]

One problem with putting SVN on CTM seems to be the file 
base/db/repo-cache.db.

I have no idea what this file is for, or even if it is necessary.  I 
have done a lot of googling, and I'm not finding much useful information.

This is a huge file (about 85M).  It is not a text file, so every time 
it is changed, the next CTM delta contains the entirety of this file. 
With compression, this will make each delta about 40M.

Does anyone know what this file is good for?

By the way, updating the src CTM's should be a breeze using the svn 
depository.