RDS SQL Server Standard - Recurring CPU Utilization Spikes

Hi, did you get any query information from performance insight or profile on queries running on particular times? Look like some scheduled tasks are running which cause the CPU spike.

I am sharing some common reasons for RDS SQL server CPU spike.

1. Query Inefficiency: Poorly optimized or resource-intensive queries can place a heavy load on the CPU. Addressing this issue may involve adding indexes, rewriting queries, or utilizing query hints.
2. High Concurrency: Multiple concurrent connections and queries executing simultaneously can strain the CPU resources. Optimizing connection pooling and scaling up the instance size may be required to handle high concurrency scenarios.
3. Database Maintenance Tasks: Operations like index rebuilds, database consistency checks (DBCC), or statistics updates can be CPU-intensive, especially for large databases. Scheduling these tasks during off-peak hours and monitoring their impact is recommended.
4. Memory Constraints: Insufficient memory allocation can force the SQL Server to rely more heavily on disk operations, leading to increased CPU usage. Ensuring adequate memory allocation for the SQL Server instance is crucial.
5. Blocking and Deadlocks: Frequent blocking or deadlock situations, often caused by inefficient application design or queries, can result in CPU spikes as the SQL Server attempts to resolve these issues. Addressing blocking and deadlocks through application design improvements or query optimization is advisable.
6. Inadequate Instance Size: If the chosen instance type lacks sufficient CPU resources to handle the workload, CPU spikes may occur. Scaling up to a larger instance type with more CPU resources may be necessary.
7. Code-related Issues: Poorly written application code or inefficient database design can contribute to CPU spikes, as the SQL Server may need to compensate for these issues, leading to increased CPU usage.

To troubleshoot and mitigate CPU spikes, below tools can be leveraged.

CloudWatch matrices, Performance Insight, Enhanced monitoring & SQL Server native tools

You can refer to AWS Article on How do I troubleshoot high CPU utilization on my RDS for SQL Server instance for more details, also you can reach out to AWS support to get more information.