We use analytics and advertising cookies to understand how the site is used and whether our ads on Facebook and Instagram work. They are set only if you accept. See our Privacy Policy for details.
DynamoDB interviews are data-modelling interviews. You will be given an access pattern and asked for a key design, then pushed on what breaks at scale: a hot partition, a GSI that throttles the table, a scan that should have been a query, a write that must not happen twice.
Each question below is a scenario with four plausible answers and an explanation.
Answer a real AWS interview question before you browse the DynamoDB list. No signup needed.
A content management application runs on EC2 instances in an Auto Scaling group across three Availability Zones. Every instance must read and write the same set of user-uploaded files through a standard file system interface (POSIX), and files must remain available if an AZ fails. Which storage solution should a solutions architect choose?
Practice in a session
10 questions from AWS, one after another, then your score and streak.
Partition and sort key design, hot partitions and adaptive capacity, global vs local secondary indexes, single-table design, query vs scan, on-demand vs provisioned capacity, conditional writes and optimistic locking, transactions, DynamoDB Streams, TTL, and eventually vs strongly consistent reads.
A local secondary index keeps the table's partition key with a different sort key, must be defined when the table is created, shares the 10 GB limit per item collection, and supports strongly consistent reads. A global secondary index can use any partition and sort key, can be added at any time, has its own capacity, and supports only eventually consistent reads.
A key with low cardinality or a time-based key (such as today's date) sends most traffic to one partition, and a single partition serves at most 3,000 read and 1,000 write capacity units per second. Adaptive capacity absorbs some skew, but the fix is a higher-cardinality key or write sharding - adding a calculated suffix to spread one logical key across partitions.
On-demand bills per request and suits new, spiky or unpredictable workloads. Provisioned capacity with auto scaling suits steady, predictable traffic and is cheaper at high sustained utilisation, optionally with reserved capacity. Interviewers want you to tie the choice to the traffic shape and cost.