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Yes, high availability with ACID and 'eventual consistency' on reads. I never understood why an eventually consistent datastore could qualify as ACID because in the real world if you need ACID, then eventual consistency is never good enough.

It's good to see Google roll this service out separately from GAE but it's not as good as DynamoDB or data services from Parse and others.

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You only have eventual consistency for queries outside of entity‐groups. For ancestor queries you get strong consistency.

https://developers.google.com/appengine/docs/python/datastor...

Imagine a comment system. You’d fire one global query with eventual consistency guarantees for all comments in a thread and another one in parallel for only comments made by the signed in user. Merging the two gives you the best of both – great scalability and consistency where it matters.

> it's not as good as DynamoDB

DynamoDB’s transaction support is limited to incrementing counters and optimistic concurrency on a single item. Compared to Datastore, it looks like a toy.

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