AWS DevOps Engineer Professional Practice Test

What are some differences between Global and Local Secondary Indexes for DynamoDB?

1. Local can be created anytime, whereas Global cannot

2. Local only queries a single partition and consumes capacity from the base table

3. Global indexes can only be created at table creation

4. Global indexes use less capacity than Local indexes

The correct answer is: Local only queries a single partition and consumes capacity from the base table

The chosen answer highlights an important aspect of Local Secondary Indexes (LSIs) in DynamoDB. Local Secondary Indexes are specifically designed to allow querying within a single partition key, meaning they maintain the same partition as the base table but permit different sorting attributes, which is a significant operational capability. Because LSIs are tied to a single partition, they utilize capacity from that partition's data, which can be advantageous as it helps optimize performance for queries specific to that partition. In contrast, Global Secondary Indexes (GSIs) are defined to support querying across all partitions in a table, which makes them more flexible for wide-ranging queries but also means they can consume additional read/write capacity based on the table's overall traffic. While LSIs can only be created during table creation and cannot be modified later, GSIs can be added or removed after the table is created. The suggestion that local indexes can be created anytime is misleading since they can only be defined upon initial table creation. Furthermore, the overall capacity usage of GSIs is not necessarily less than that of LSIs; it varies based on specific query patterns, so claiming global indexes inherently use less capacity is an overgeneralization. Therefore, the characteristics of Local Secondary Indexes indeed emphasize their functionality tied