Q:

app engine upload mechanisme for changed data, does it upload whole or delta?

I upload my_app to  app engine app by:  
appcfg.py update c:\my_app ...
If I already uploaded for my_app then done a minor changement in file, 

Does it upload whole project to app engine and overwrite whole previous project?
Or does it upload only relevent change and overwrite relevent part?

And what is the case for the issue for this command:  
bulkloader.py --restore --filename=my_kind.dump ... 

A:

Did you try it?
update uploads the whole application each time. There's no concept of a delta. Normally, when you upload a new version I would suggest changing the version setting - that way you can keep up to 10 previous versions of your app on the site, and only set the new one to be the default once you are sure it is working.
If you upload without changing the version, AppEngine actually creates a new version before deleting the old one, so you need a spare slot in your versions list.
I don't understand your question about the bulkloader. Are you asking if that does a delta? No, it can't, because it sends the data serially via the remote API - there's no way for it to know in advance which rows in your data file already exist in the datastore.

