Does ID always increase when adding new objects to GAE Datastore?

I'm building an client/server-app where I want to sync data. I'm thinking about including the largest key from the local client database in the query so the 开发者_如何学Pythonserver can fetch all entities added after that entity (with key > largest_local_key).

1. Can I be sure that the Google App Engine always increase the ID of new entities?
2. Is that a good way to implement synchronization?

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No, IDs do not increase monotonically.

Consider synchronizing based on a create/update timestamp.