What's causing the sudden increase in Algolia's API response times for geo-search queries in the European region?

Introduction

The sudden increase in Algolia's API response times for geo-search queries in the European region is a critical issue that demands immediate attention. This performance degradation directly impacts user experience and could lead to customer churn if not addressed promptly. I'll approach this problem systematically, focusing on identifying the root cause, validating hypotheses, and developing both short-term fixes and long-term solutions.

Step 1

Clarifying Questions (3 minutes)

• Looking at the timing, I'm thinking this might be related to recent infrastructure changes. Have there been any significant updates to our European data centers or CDN configurations in the past week?

Why it matters: Infrastructure changes often impact API performance. Expected answer: Yes, there was a recent CDN configuration update. Impact on approach: If confirmed, we'd focus on rolling back or optimizing the CDN configuration.

• Considering the specificity to geo-search queries, I'm wondering about data indexing. Has there been any change in how geo-data is indexed or stored recently?

Why it matters: Indexing changes can significantly affect query performance. Expected answer: No recent changes to geo-data indexing. Impact on approach: If no changes, we'd look at other factors like data volume or query complexity.

• Given the regional nature, I'm curious about traffic patterns. Have we seen any unusual spikes in geo-search query volume from European users?

Why it matters: Unexpected traffic surges can strain systems and increase response times. Expected answer: Traffic has been within normal ranges. Impact on approach: If traffic is normal, we'd focus more on internal system issues rather than capacity problems.

• Thinking about potential data issues, has there been any recent update to the European geo-data set that Algolia uses?

Why it matters: Data quality or volume changes can impact query performance. Expected answer: A recent update added more granular location data for several European countries. Impact on approach: If confirmed, we'd investigate how this data update might be affecting query processing.