What caused the sudden spike in failed transactions for EvenUp's group expense tracking tool last Thursday?

Introduction

The sudden spike in failed transactions for EvenUp's group expense tracking tool last Thursday 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 the product.

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 week?

Why it matters: Recent changes often correlate with sudden performance issues. Expected answer: Yes, a new feature was deployed on Wednesday. Impact on approach: If confirmed, we'd focus on the new feature and its integration.

• Considering the nature of group expense tracking, I'm wondering about transaction volume. Was there an unusual spike in user activity or transaction attempts around the time of the incident?

Why it matters: Unusual activity could indicate a capacity issue or a popular event triggering mass usage. Expected answer: Transaction volume was within normal range. Impact on approach: If normal, we'd shift focus from capacity issues to other potential causes.

• Given that it's a group tool, I'm curious about the user segments affected. Was this issue widespread or concentrated among specific user groups or geographic regions?

Why it matters: Localized issues might point to regional infrastructure problems or specific user behaviors. Expected answer: The issue affected users across all segments and regions. Impact on approach: A widespread issue would suggest a core system problem rather than a localized one.

• Thinking about the metric itself, I'm wondering about the definition of "failed transactions." Has there been any recent change in how we define or measure transaction failures?

Why it matters: Changes in metric definition can sometimes create false alarms. Expected answer: No changes in the definition or measurement of failed transactions. Impact on approach: If confirmed, we'd focus on actual system issues rather than measurement anomalies.