Exam Professional Cloud Database Engineer topic 1 question 105 discussion

Option B: Cloud Spanner ✅ 99.999% availability for multi-region configurations (exceeds 99.99% requirement) ✅ Global distribution with automatic scaling ✅ High write throughput with horizontal scaling ✅ Low latency writes with global replication ✅ Durable and consistent - ACID transactions globally ✅ Elastic scaling - automatically handles traffic spikes Not D Option D: Bigtable ✅ High write throughput and low latency ✅ Elastic scaling ❌ NoSQL - less suitable for ecommerce transactions requiring ACID properties ❌ Eventually consistent - not ideal for shopping cart operations ❌ Complex application logic needed for ecommerce use cases

Bigtable is elastically scalable and has vastly lower latency than Spanner and also is routinely used for shopping cart functions. Spanner is nearly a magnitude slower in this write-heavy context. I disagree that B is the correct answer.

if the data from shooping kart is transactional, then Yes B, else it should be D

very low latency = Bigtable

Spanner because "Global" eliminates others

B. Global eliminates Cloud SQL (A). Memorystore is a cache not a data storage solution. Eliminate C. Spanner has multi-region but doesn’t autoscale (unless you use Autoscaler). Bigtable instances can be in different regions and does autoscale. Both Bigtable and Spanner can handle the writes and uptime. The word “durable” and no mention of huge quantities of data suggests the best answer is B, Cloud Spanner.

B Note that what BT differ with Spanner is BT can't do very high throughput (insert single row one-by-one) and low latency at the same time. The official document suggested we should do that in batch; that's a rare case in the shopping cart and no customer will like to wait till other customers finishing their transaction so BT could handle together. Plus, it's hard for BT handling join, e.g. complex upsale, different type of products, etc. Uptime 99.9% => BT, Spanner Low latency write => BT, Spanner High throughput low latency => Spanner ECommerce & Shopping cart => SQL => Spanner https://cloud.google.com/bigtable/docs/writes

oogle Cloud Spanner is a highly scalable, reliable, and fully managed relational database service that runs on Google's infrastructure. It's designed to handle large amounts of data and provide high availability, even in the face of failures. Spanner can be used to store and manage data for a variety of applications, including e-commerce websites. Spanner is a good choice for this scenario because it can handle high write throughput and provides 99.99% uptime. It's also a good fit for applications that need to be highly available, even in the face of failures.

B- I will go with Spanner because it is a GLOBAL website and BT has a zonal location https://cloud.google.com/bigtable/docs/locations even it supports replication https://cloud.google.com/bigtable/docs/replication-overview It doesn't mention ACID but it mentions durable

Low latency writes => BigTable No mention ACID here then my vote D

Scalable, =>99,99, low write latency -> Spanner

B: Use Cloud Spanner for data storage. Cloud Spanner Service Level Agreement (SLA) During the term of the agreement under which Google has agreed to provide Google Cloud Platform to Customer (as applicable, the "Agreement"), the Covered Service will provide a Monthly Uptime Percentage to Customer as follows (the "Service Level Objective" or "SLO"): Covered Service Monthly Uptime Percentage Cloud Spanner - Multi-Regional Instance >= 99.999% Cloud Spanner - Regional Instance >= 99.99%