I've been using Viewpoint to sync Calendar Items from a user folder, using AllProperties as sync shape, but even for something at/around 400-500 entries, the memory usage of the synchronizing Ruby process grows to over 1GB (but remains constant there). The actual XML data exchanged on the wire for syncing that contact folder is less than 1MB, so that's a ratio of 1:1000, which leads me to believe that rather there's a memory leakage (or some form of problem reclaiming memory) when instantiating contacts.
I've not dug deeper (yet) as to the causes of the memory usage - the only thing I can think of is that the construction of Mailbox/Attendee-objects takes up this much space - but still, that shouldn't cause a gig of memory usage for just 400-500 contacts.
Anything known about this? I'll debug deeper anyway, so this is just a "heads up."
I'm still looking into this. I wrote some test code and could never find out where it was holding onto memory. Once I get my pre-v1 branch a little more stable I'll try the test there to see if it still exists. I'm ripping out the Handsoap dependency for v1 so that may be a factor.
I'm finally getting around to actively developing v1 again. It changes quite a bit from a backend / parsing perspective so I'm going to close this for now unless it pops up again in 1.0.