What's causing the sudden 30% increase in failed message deliveries across Slack workspaces?

Introduction

The sudden 30% increase in failed message deliveries across Slack workspaces is a critical issue that demands immediate attention. This analysis will systematically identify, validate, and address the root cause while considering both short-term fixes and long-term implications for Slack's messaging infrastructure.

I'll approach this problem by first clarifying the context, then ruling out external factors before diving deep into the product's user journey and metrics. We'll generate data-driven hypotheses, conduct root cause analysis, and develop a comprehensive plan for validation and resolution.

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 to Slack's messaging infrastructure in the past week?

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

• Considering the scale, I'm wondering if this is affecting all users equally. Are we seeing this 30% increase uniformly across all workspaces, or is it concentrated in specific segments?

Why it matters: Helps narrow down potential causes and affected user groups. Expected answer: The issue is more prevalent in larger workspaces. Impact on approach: We'd investigate scalability issues in message delivery systems.

• Given the nature of the problem, I'm curious about the error messages. What specific error codes or messages are we seeing associated with these failed deliveries?

Why it matters: Error codes can provide crucial clues about the nature of the failure. Expected answer: We're seeing a mix of timeout errors and "message not delivered" notifications. Impact on approach: This would guide our technical investigation towards network issues or database bottlenecks.

• Thinking about potential data anomalies, has there been any change in how we're measuring or defining "failed message deliveries" recently?

Why it matters: Ensures we're not dealing with a measurement issue rather than an actual problem. Expected answer: No changes in measurement or definition. Impact on approach: Confirms we're dealing with a real increase in failures, not a reporting anomaly.