Claude Code
database
Database Deadlock in Concurrent Updates
Application encounters deadlock errors intermittently when multiple users perform operations simultaneously. Specific sequences of operations cause deadlock: Thread A waits for lock held by Thread B, which waits for lock held by Thread A. Application must retry deadlocked operations.
Deadlocks are hard to reproduce but fail under load testing or in production.
Error Messages You Might See
Deadlock found when trying to get lock
Transaction was rolled back due to deadlock
Continuous deadlock retries
Common Causes
- Transactions acquire locks in different order (A locks table1 then table2, B locks table2 then table1)
- Long-running transactions holding locks too long
- Missing indexes causing full table scans and excessive row locks
- Row-level locks held while waiting for other operations
- No deadlock retry logic in application
How to Fix It
Always acquire locks in same order across application. Use consistent transaction isolation level. Keep transactions short. Add indexes to reduce lock contention. Implement deadlock retry: catch deadlock exception, wait briefly, retry. Check database: SHOW PROCESSLIST shows locks held. Configure deadlock victim: database kills one transaction to resolve.
Real developers can help you.
Milan Surelia
Milan Surelia is a Mobile App Developer with 5+ years of experience crafting scalable, cross-platform apps at 7Span and Meticha. At 7Span, he engineers feature-rich Flutter apps with smooth performance and modern UI. As the Co-Founder of Meticha, he builds open-source tools and developer-focused products that solve real-world problems.
Expertise:
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Notable Achievements:
🎯 Revamped the Vepaar app into Vepaar Store & CRM with a 2x performance boost and smoother UX.
🚀 Launched Compose101 — a Jetpack Compose starter kit to speed up Android development.
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🎖️ Worked on improving app performance and user experience with smart solutions.
Milan is always happy to connect, work on new ideas, and explore the latest in technology.
Rudra Bhikadiya
I build and fix web apps across Next.js, Node.js, and DBs.
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Richard McSorley
Full-Stack Software Engineer with 8+ years building high-performance applications for enterprise clients. Shipped production systems at Walmart (4,000+ stores), Cigna (20M+ users), and Arkansas Blue Cross. 5 patents in retail/supply chain tech. Currently focused on AI integrations, automation tools, and TypeScript-first architectures.
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Basel Issmail
’m a Senior Full-Stack Developer and Tech Lead with experience designing and building scalable web platforms. I work across the full development lifecycle, from translating business requirements into technical architecture to delivering reliable production systems.
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Developer with 8 years of experience building softwares fro startups
You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.
Get HelpFrequently Asked Questions
How to prevent deadlocks?
Always acquire locks in same order. If A acquires table1 then table2, B must too (never table2 then table1).
How to detect deadlock cause?
Enable deadlock logging: innodb_print_all_deadlocks = ON (MySQL). Logs show which queries caused it and lock order.
Should deadlocks be retried?
Yes. Deadlocks are normal under load. Catch DeadlockException, wait briefly (exponential backoff), retry. Usually succeeds on second try.