Lock contention or deadlock

Cases

1. IL-0570 Dropping an unused MySQL table stalled queries on its busy parent table and crowdworks.jp was hard to reach for a minuteCrowdWorks · 2026

   Root cause Faulty deployment

2. IL-0322 A GCP storage incident degraded the disk under GitLab.com's primary PostgreSQL and caused two bursts of site-wide 503sGitLab · 2026 · sev1

   Root cause Cloud provider outage

3. IL-0510 MIT Learn's RDS PostgreSQL ran out of storage after a release and learn.mit.edu returned 503s and 504s for hoursMIT Open Learning · 2026

   Root cause Faulty deployment

4. IL-0487 Autumn's Postgres CPU spiked and about 10% of API requests failed after a collation change left the main query unindexedAutumn · 2026

   Root cause Configuration change

5. IL-0318 Clerk's APIs went down with lock contention and 429s while a Google Cloud SQL live migration slowed its database diskClerk · 2026

   Root cause Cloud provider outage

6. IL-0369 Railway's backend API went down when a column migration waited on locks and replicas could not get database connectionsRailway · 2025

   Root cause Faulty deployment

7. IL-0315 Railway's backend API went down when an index build locked a billion-row Postgres table and used up every connectionRailway · 2025

   Root cause Faulty deployment

8. IL-0436 A supremum lock left by ROLLBACK TO SAVEPOINT in a long transaction blocked inserts and filled Aurora MySQL connectionsfreee · 2025

   Root cause Software defect

9. IL-0557 Database transaction locks piled up on Storj's US1 satellite, and uploads and downloads failed with timeouts for 2 hoursStorj · 2025

   Root cause Capacity exhaustion

10. IL-0329 A routine migration left PGAudit stuck holding Postgres locks, causing intermittent timeouts and a 2-minute outageincident.io · 2025

    Root cause Software defect

11. IL-0556 A transaction left open during database maintenance stopped uploads and then downloads on Storj's US1 satelliteStorj · 2024

    Root cause Operator error

12. IL-0217 Honeycomb's main MySQL database locked up under cache-miss reads and ran out of connections, a 68-minute total outageHoneycomb · 2023

    Root cause Software defect

13. IL-0483 Replicate's website and API returned slow responses and HTTP 500s for two hours as PostgreSQL connections ran outReplicate · 2023

    Root cause Faulty deployment

14. IL-0524 An index migration locked Open Collective's whole Transactions table and degraded the service for nearly an hourOpen Collective · 2023

    Root cause Faulty deployment

15. IL-0314 Daily's newly upgraded Aurora MySQL database deadlocked on meeting-event queries and its call servers kept restartingDaily · 2023

    Root cause Breaking change in an upgrade

16. IL-0301 Basecamp 3's primary database went into total gridlock at the top of the hour and Basecamp 3 went down twice37signals · 2022

    Root cause Capacity exhaustion

17. IL-0385 GitHub MySQL read replicas hit a semaphore deadlock during a schema migration's table rename and kept crash-recoveringGitHub · 2021

    Root cause Software defect

18. IL-0441 A ZOZO SQL Server database stalled and applications hit timeout storms whenever batch executions peaked in salesZOZO · 2021

    Root cause unknown

19. IL-0486 Figma's PostgreSQL 9 database on RDS slowed under high write IOPS and lock contention until the site was unavailableFigma · 2020

    Root cause Software defect

20. IL-0457 The HA HDFS NameNode of a log-collection Hadoop cluster failed over around 09:00 after its ZKFC health check timed outLINE · 2019

    Root cause Capacity exhaustion

21. IL-0391 GoCardless API requests timed out for about 15 seconds while a Postgres migration waited for an AccessExclusive lockGoCardless · 2015

    Root cause Faulty deployment