Which solution will meet these requirements?

Explanations:

Decreasing the number of vCPUs will reduce the database’s processing capacity, which is counterproductive during peak usage. While increasing themax_connectionssetting may temporarily alleviate the issue, it does not address the underlying problem of connection management and could lead to further performance degradation if the database resources are insufficient.

Using Amazon RDS Proxy provides a managed, highly available connection pool that can efficiently manage and share database connections among the Lambda functions. This helps mitigate the “too many connections” issue, allowing the application to handle variable workloads without overwhelming the database. It also adds resilience by automatically managing connections and reducing the likelihood of hitting connection limits.

Adding a CloudWatch alarm to change the DB instance class based on the number of connections does not provide a proactive solution. Changing instance classes dynamically can lead to increased downtime and does not address immediate connection issues. Furthermore, scaling up may not be feasible quickly enough during peak load times.

An EventBridge rule to increase themax_connectionssetting based on CPU utilization may not effectively address the problem since the limit on connections is not necessarily tied to CPU utilization. Additionally, changing themax_connectionssetting does not manage the existing connection pool effectively and could still lead to the application being overwhelmed during peak times.