A company is using an Amazon Redshift cluster to run analytics queries for multiple sales teams. In addition to the typical workload, on the last…

The core issue is a predictable surge in concurrent read queries from thousands of users, leading to performance degradation. Amazon Redshift Concurrency Scaling is designed specifically for this scenario. It automatically adds and removes transient cluster capacity to handle bursts of read queries, ensuring consistently fast performance without requiring manual intervention or causing downtime. By enabling this feature on the relevant Workload Management (WLM) queues, the cluster can elastically scale its query processing power to meet the monthly demand surge, directly addressing the performance bottleneck without impacting availability.

A. Classic Resize: This operation makes the cluster read-only for an extended period, which significantly impacts availability and violates a key requirement of the solution.

B. Elastic Resize: While faster than classic resize, this operation still causes a brief period of cluster unavailability (a few minutes) as connections are dropped, violating the requirement.

D. Redshift Spectrum: This feature is for querying data directly in Amazon S3. It does not add compute capacity to the main cluster to handle an increased number of concurrent queries.

1. Amazon Redshift Documentation

"Concurrency scaling": "With concurrency scaling

you can support virtually unlimited concurrent users and concurrent queries

with consistently fast query performance. When you enable concurrency scaling

Amazon Redshift automatically adds additional cluster capacity when you need it to process an increase in concurrent read queries." This source confirms that Concurrency Scaling is the correct mechanism for handling query concurrency surges.

2. Amazon Redshift Documentation

"Resizing clusters - Elastic resize": "During an elastic resize

the cluster is unavailable for a few minutes... We recommend that you schedule an elastic resize during a time of low query activity." This confirms that elastic resize impacts availability.

3. Amazon Redshift Documentation

"Resizing clusters - Classic resize": "During a classic resize

Amazon Redshift places your existing cluster into read-only mode..." This confirms that classic resize impacts write availability.

4. Amazon Redshift Documentation

"Working with Concurrency Scaling": "To enable concurrency scaling

you configure the concurrencyscalingmode parameter in your workload management (WLM) configuration." This supports the implementation detail mentioned in the correct answer.

5. Amazon Redshift Documentation

"Querying external data using Amazon Redshift Spectrum": "Amazon Redshift Spectrum... enables you to run Amazon Redshift SQL queries against exabytes of data in Amazon S3." This clarifies that Spectrum's purpose is for querying external data

not scaling for concurrency on the main cluster.