Exam AZ-304 topic 3 question 43 discussion

Bounded staleness https://docs.microsoft.com/en-us/azure/cosmos-db/consistency-levels Bounded staleness is frequently chosen by globally distributed applications that expect low write latencies but require total global order guarantee. Bounded staleness is great for applications featuring group collaboration and sharing, stock ticker, publish-subscribe/queueing etc.

B: Strong ? https://docs.microsoft.com/ja-jp/azure/cosmos-db/consistency-levels

Seems correct

"Provide a latency-based Service Level Agreement (SLA) for writes." is actually the key here I think. For Azure Cosmos accounts configured with strong consistency with more than one region, the write latency is equal to two times round-trip time (RTT) between any of the two farthest regions, plus 10 milliseconds at the 99th percentile. High network RTT between the regions will translate to higher latency for Cosmos DB requests since strong consistency completes an operation only after ensuring that it has been committed to all regions within an account. The exact RTT latency is a function of speed-of-light distance and the Azure networking topology. Azure networking doesn't provide any latency SLAs for the RTT between any two Azure regions, however it does publish Azure network round-trip latency statistics. https://docs.microsoft.com/en-us/azure/cosmos-db/consistency-levels

Strong consistency for accounts with regions spanning more than 5000 miles (8000 kilometers) is blocked by default due to high write latency. To enable this capability please contact support. In session consistency, within a single client session reads are guaranteed to honor the consistent-prefix, monotonic reads, monotonic writes, read-your-writes, and write-follows-reads guarantees. In consistent prefix option, updates that are returned contain some prefix of all the updates, with no gaps. Consistent prefix consistency level guarantees that reads never see out-of-order writes. Answer is A

A bounded stateless due to - https://docs.microsoft.com/en-us/azure/cosmos-db/consistency-levels#write-latency-and-strong-consistency this paragrpah "For Azure Cosmos accounts configured with strong consistency with more than one region, the write latency is equal to two times round-trip time (RTT) between any of the two farthest regions, plus 10 milliseconds at the 99th percentile. High network RTT between the regions will translate to higher latency for Cosmos DB requests since strong consistency completes an operation only after ensuring that it has been committed to all regions within an account. The exact RTT latency is a function of speed-of-light distance and the Azure networking topology. Azure networking doesn't provide any latency SLAs for the RTT between any two Azure regions, however it does publish Azure network round-trip latency statistics."