Development with AWS services
⏱ ~3-min readAceMark Guide
What this topic is really about
DAX is a fully managed, DynamoDB-compatible in-memory cache that delivers microsecond reads without code changes to the DynamoDB API calls. ElastiCache is general-purpose and requires more integration work, CloudFront caches web content, and S3 Transfer Acceleration speeds S3 uploads.
Configuring a Lambda function with VPC settings (subnet IDs and security groups) gives it elastic network interfaces in the VPC so it can reach private resources like RDS. Provisioned concurrency reduces cold starts, and stage variables are API Gateway config, not networking.
See the mechanism
Strongly consistent reads return the latest committed write at 2x the RCU of eventually consistent. A diagram for this topic isn't available yet — the worked example below walks the same reasoning step by step.
An exam-style question, fully explained
Which DynamoDB read mode returns the most up-to-date data but costs more capacity units?
- Identify what the question tests: Which DynamoDB read mode returns the most up-to-date data but costs more capacity units.
- Strongly consistent reads return the latest committed write at 2x the RCU of eventually consistent.
- Eventually consistent may miss the most recent write but is cheaper.
- Transactional reads cost even more (ACID across multiple items).
- Streamed is not a read mode.
Traps the examiner sets
- Read each option carefully — distractors on Development with AWS services are designed to look plausible.
- Re-check the exact wording of the question stem before committing to an answer.
- Watch the qualifiers ("always", "only", "except") that flip a correct-looking option.
Test your recall
Answer each from memory — you'll see instantly whether you're right and why.
Run a focused 10-question mini-mock on Development with AWS services and see it stick.
Practice more of this topic →