Exam Professional Cloud Database Engineer topic 1 question 12 discussion

D. A is nonsense. Using interleaved tables can help speed up queries, but the question says query response times are OK. So B is wrong. C is wrong for the same reason. That leaves D. The question is about which factors determine the cost of running Spanner. They include region vs. multi-region, compute unit (nodes or processing units), how much storage and how much backup space. From the Google docs, it says “When you create a Cloud Spanner instance, you choose the number of compute capacity nodes or processing units to serve your data. However, if the workload of an instance changes, Cloud Spanner doesn't automatically adjust the size of the instance. This document introduces the Autoscaler tool for Cloud Spanner (Autoscaler), an open source tool that you can use as a companion tool to Cloud Spanner. This tool lets you automatically increase or reduce the number of nodes or processing units in one or more Spanner instances based on how their capacity is being used.” https://cloud.google.com/spanner/docs/autoscaling-overview

It’s D

Autoscaling is the way to go here. D.

Granular instance is available in Public Preview. With this feature, you can run workloads on Spanner at as low as 1/10th the cost of regular instances, https://cloud.google.com/blog/products/databases/get-more-out-of-spanner-with-granular-instance-sizing

As the others say - use autoscaling to rightsize the cluster

D: Use granular instance sizing in Cloud Spanner and Autoscaler.

D is the correct answer, https://cloud.google.com/architecture/autoscaling-cloud-spanner

Correct answer - D