[daxfohl]

Are graph ops/queries atomic? i.e. if you run a tree query on a tree-graph, at the same time you're re-parenting a treenode, is there a chance that the node could end up in the result tree twice or zero times?

Also, if they're atomic, are they optimistic or pessimistic transactions? Also if they're atomic, does that mean queries done on the write server? (My understanding is that readonly transactions on read-replicas are not supported, or at least they weren't under DocDB).

Any lay-programmer insight into what's going on under the hood, or at least performance/atomicity implications, without giving up too much proprietary info, would be appreciated.

[dharmashuklaMS]

Read only transactions existed in DocumentDB too. DocumentDB was a strict subset of the capabilities that Cosmos DB provides/existed underneath. Hence, read only transactions exist in Cosmos DB too. The first technical overview blog post attempted to provide you a high level overview. We are hoping to cover specific areas in either future blog posts, conference publications.