Incident Library

Component

Query planner and table statistics

쿼리 플래너와 테이블 통계 · query-planner

3 cases · 2022 to 2026

Root cause Faulty deployment1Query plan regression1Breaking change in an upgrade1
Contributing factor Monitoring blind spot2Unverified assumption1Automation amplification1Inefficient query1Unrepresentative staging1
Symptom Database overload3High latency3Service outage2Connection pool exhaustion1High error rate1
Organisation CircleCI1Clerk1RevenueCat1

Cases, by severity

  1. IL-0317 Clerk's Postgres slowed after an automatic analyze flipped a query plan, and over 95% of requests got 429Clerk · 2026

    Root cause Query plan regression

  2. IL-0327 After a blue/green upgrade of CircleCI's workflows database every query hit disk, and workflow starts lagged or failedCircleCI · 2025

    Root cause Faulty deployment

  3. IL-0308 Most RevenueCat backend systems failed after cutover to a new Aurora PostgreSQL 14 cluster as queries became very slowRevenueCat · 2022

    Root cause Breaking change in an upgrade

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