A mobile game stores one profile document per player and looks it up by player id on every session. It needs single-digit millisecond responses, the player count may go from a hundred to two million in a week after a marketing push, and there are no joins or reporting queries. Which database fits?
AWS Certified Cloud Practitioner (CLF-C02), objective 3. Cloud technology and services medium
Machine-checked — no person has signed for it. This question was read against the source cited below by an automated pass, which found no contradiction. That is a weaker claim than it sounds: the same kind of process wrote the question, so it can confirm its own mistake.
Treat it as a good draft rather than as settled fact, and read the source below before you rely on it. It is not used in mock exams here — only questions a person has signed for are.
The options
Correct Amazon DynamoDB
Correct. It is built for exactly this access pattern: lookups by key at consistent single-digit millisecond latency, no servers to size, and on-demand capacity that absorbs an unpredictable launch without anyone provisioning for it.
Not correct Amazon RDS on a large instance class
Wrong. You would be paying for relational features the workload never uses, and — the real problem — you must choose an instance class in advance for a load nobody can predict.
Not correct Amazon Redshift
Wrong. Redshift is a data warehouse: columnar storage optimised for analytical scans over large datasets. Fetching one player's row per request is the workload it is least suited to.
Not correct Amazon S3, one object per player
Wrong. It would store the documents, but object storage gives you no item-level updates, no conditional writes and no query beyond the key, and it is not built for per-request latency at this level.
Why
Pick the database from the access pattern, not from the data's size. Lookups by key at any scale with a flexible schema go to DynamoDB. Joins, transactions across tables and existing SQL go to RDS or Aurora. Large analytical scans go to Redshift. Graph relationships go to Neptune, time series to Timestream, in-memory speed to ElastiCache or MemoryDB. The mistake to avoid is choosing relational by habit and then fighting it at scale.
Where this comes from
- Cited
- AWS exam guide task statement 3.4
Practise this
Reading one question is not practice. The trainer will draw a set from objective 3 and space the ones you get wrong.
Practise AWS Certified Cloud Practitioner (CLF-C02)
More questions on this objective
- A team builds the same stack — a load balancer, three EC2 instances and a database — by clicking through the console once for dev, once for test and once for production. The three environments have quietly drifted apart and a bug that only appears in production took a week to trace to a missing setting. They want the stack described once, reviewed in a pull request, and applied identically to each environment. Which service does that? machine-checked
- A Python reporting job runs unattended every night. Inside its own logic it needs to list objects in an S3 bucket, read a few of them, and write a summary object back, handling failures with the program's existing retry and logging code. What is the appropriate way for that program to call AWS? machine-checked
- A small team has a Java web application and no operations staff. They want to hand AWS the application package and have it provision the instances, the load balancer and the scaling policy, while keeping the ability to inspect and adjust those resources later if they need to. Which service fits? machine-checked
- A manufacturer keeps its plant-floor control application on servers inside the factory, because production must continue when the internet link drops. Its reporting and analytics run in AWS and read the same production data. Which TWO statements about this arrangement are accurate? machine-checked
- An internal application runs on a single EC2 instance in one Availability Zone. During a power event in that Availability Zone the application was unreachable for four hours. The team wants the cheapest change that keeps it serving through the same kind of event, without moving to another Region. What should they do? machine-checked
- A German insurer is told by its regulator that customer records must remain within the European Union. Four candidate Regions can all run every service the workload needs, and one of them is noticeably cheaper per instance-hour. Which consideration settles the choice of Region first? machine-checked