What caused the sudden spike in query latency for Devo's real-time analytics dashboard yesterday afternoon?

Introduction

The sudden spike in query latency for Devo's real-time analytics dashboard yesterday afternoon is a critical issue that demands immediate attention. As we dive into this analysis, we'll systematically investigate potential causes, validate hypotheses, and develop a comprehensive solution strategy. Our approach will balance the need for quick resolution with long-term improvements to 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 system in the past 24-48 hours?

Why it matters: Recent changes often correlate with performance issues. Expected answer: Yes, a new feature was deployed yesterday morning. Impact on approach: If confirmed, we'd focus on the new deployment as a primary suspect.

• Considering the nature of real-time analytics, I'm curious about data volume. Have we seen any unusual spikes in data ingestion or query complexity recently?

Why it matters: Increased data load can strain system resources. Expected answer: Data volume has been steadily increasing, but no sudden spikes. Impact on approach: If true, we'd need to investigate scaling and optimization strategies.

• Given that it's a dashboard issue, I'm wondering about user behavior. Has there been any change in user patterns or an influx of new users?

Why it matters: Changes in usage patterns can impact system performance. Expected answer: No significant changes in user behavior or numbers. Impact on approach: If confirmed, we'd shift focus to internal system issues rather than user-related factors.

• Thinking about the broader ecosystem, have there been any changes to underlying infrastructure or third-party services?

Why it matters: External dependencies can significantly impact performance. Expected answer: No known changes to infrastructure or services. Impact on approach: If true, we'd focus more on our internal systems and code.

• Considering the specificity of "yesterday afternoon," I'm curious about any scheduled maintenance or cron jobs. Were any background processes or maintenance tasks running during that time?

Why it matters: Scheduled tasks can compete for resources and impact performance. Expected answer: Regular maintenance was scheduled for yesterday afternoon. Impact on approach: If confirmed, we'd investigate potential resource conflicts and scheduling optimizations.