What caused the sudden spike in latency for Aurora's image recognition API last week?

Introduction

The sudden spike in latency for Aurora's image recognition API last week is a critical issue that demands immediate attention and thorough analysis. As we delve into this problem, we'll employ a systematic approach to identify, validate, and address the root cause while considering both short-term fixes and long-term implications for our product ecosystem.

Our analysis will follow a structured framework, beginning with clarifying questions to establish context, followed by a comprehensive examination of potential causes, data analysis, hypothesis formation, and ultimately, a robust action plan to resolve the issue and prevent future occurrences.

Step 1

Clarifying Questions (3 minutes)

• Looking at the timing, I'm thinking this could be related to a recent deployment. Has there been any significant update or change to the API or its underlying infrastructure in the past week?

Why it matters: Recent changes often correlate with performance issues. Expected answer: Yes, there was a deployment last Tuesday. Impact on approach: If confirmed, we'd focus on changes in that deployment.

• Considering the nature of image recognition, I'm curious about the data input. Have we seen any changes in the types or volumes of images being processed recently?

Why it matters: Unusual input can strain the system in unexpected ways. Expected answer: No significant changes in image types, but volume increased by 20%. Impact on approach: We'd need to investigate if the system is scaling properly with increased load.

• Given that latency is our key metric here, I'm wondering about our monitoring setup. Are we seeing this spike consistently across all instances and regions, or is it localized?

Why it matters: Helps determine if this is a global issue or specific to certain infrastructure. Expected answer: The spike is more pronounced in our US-West region. Impact on approach: We'd focus on region-specific factors and potential infrastructure issues.

• Thinking about potential external factors, have there been any changes in our third-party dependencies or cloud service providers that might impact our API performance?

Why it matters: External dependencies can significantly affect our service quality. Expected answer: No known issues with our cloud provider, but we haven't checked all dependencies. Impact on approach: We'd need to audit our dependencies and their recent performance.