Question 670
A read-heavy relational application needs scalable database access. The team confirms that a database query becomes slow after adding missing index columns. Which implementation most closely meets this requirement?
Explanation
Correct Answer
The scenario identifies this requirement: A database query becomes slow after adding missing index columns. Select Analyze query plans and implement appropriate indexes on frequently filtered columns as the specified technical mechanism. Indexing can reduce scanned rows for selective queries. This response addresses the problem described rather than a different design goal.
Incorrect Answers
The option Use RDS Proxy with tuned pool sizing and application connection reuse addresses a separate condition: a burst of Lambda invocations exhausts database connection limits. Proxy pools connections for bursty clients. The actual requirement is a database query becomes slow after adding missing index columns. Recommended corrective action: Analyze query plans and implement appropriate indexes on frequently filtered columns. Indexing can reduce scanned rows for selective queries.
Route consistency-critical reads to the writer would help if the read replica serves stale results when the application requires immediate read-after-write consistency. Asynchronous replicas can lag the primary. That is not the symptom described here: a database query becomes slow after adding missing index columns. The matching response is Analyze query plans and implement appropriate indexes on frequently filtered columns, because indexing can reduce scanned rows for selective queries.
For the alternative failure a reporting workload saturates the primary RDS database with SELECT queries, the control Add supported RDS read replicas and direct read-only traffic to them is relevant: read replicas offload reads from the writer. Here the evidence instead is a database query becomes slow after adding missing index columns. The selected technical mechanism is Analyze query plans and implement appropriate indexes on frequently filtered columns: indexing can reduce scanned rows for selective queries.