[imp] DB session = high imap load?

[Derek Harkness]

Here's the situation.  I've got Horde 3.0.5 and IMP 4.0.3, currently  
I'm using the default PHP file-base session handling.  Load on my  
IMAP server averages ~0.3 if I switch to mysql session handling load  
on the imap instantly jumps to 20+ resulting in the whole system  
grinding to a halt.  It appears that switching to the db sessions  
results in an exponential increase in authentication events.   
Switching back to file sessions and giving the imap server a minute  
to catch up bring everything back to normal.

Thoughts?

Derek