DOP-C02 Practice Question 45: DynamoDB Global Tables Multi Active
AWS Certified DevOps Engineer – Professional (DOP-C02) · Test 5 · question 5 of 10
A session store runs on an Amazon DynamoDB table in us-east-1. The company is launching in Europe and needs low-latency reads *and writes* from eu-west-1 as well as us-east-1, with replication handled for them and the ability to keep serving users if either Region becomes impaired. The application already uses the DynamoDB API and the team has no capacity to change it. Occasional concurrent writes to the same item are acceptable as long as both Regions converge on one value.
What should the team do?
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Answer:
Global tables are described as "a fully managed, multi-Region, and multi-active database feature that provides easy to use data replication and fast local read and write performance for globally scaled applications." Crucially, "any global table replica can serve reads and writes," so Europe writes locally instead of crossing the Atlantic, and applications "can achieve high resilience with a low or zero Recovery Point Objective (RPO) by shifting traffic to a different Region if application processing is interrupted in a Region." Conflicting concurrent writes are resolved with last-writer-wins, which the stem accepts, and because "global tables use existing DynamoDB APIs... no application changes are required."
Option B replicates in one direction only. Writes made in eu-west-1 never reach us-east-1, so the two Regions diverge, and the team ends up owning a stream consumer, its retries, and its failure modes, the replication solution global tables exist to remove.
Option C produces a stale copy, not a replica. A nightly restore means up to 24 hours of data loss and a table that cannot accept writes as part of the same logical dataset.
Option D is an in-Region cache in front of a single-Region table. DAX writes through to the us-east-1 table, so European writes still cross the Atlantic, and an impairment in us-east-1 takes both Regions down with it.
Reference: Global tables - multi-active, multi-Region replication