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
Deadlock found when trying to get lockTransaction was rolled back due to deadlockContinuous deadlock retries

Common Causes

  1. Transactions acquire locks in different order (A locks table1 then table2, B locks table2 then table1)
  2. Long-running transactions holding locks too long
  3. Missing indexes causing full table scans and excessive row locks
  4. Row-level locks held while waiting for other operations
  5. 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.

hanson1014 hanson1014 Full-stack developer experienced in fixing and deploying AI-generated apps from Lovable, Bolt.new, Cursor, and Replit. I specialize in debugging Supabase integration issues (auth flows, RLS policies, database connections), fixing broken deployments, resolving routing/blank screen problems, and cleaning up messy React/Vite codebases. I also build production apps with the Claude API and have shipped a Mac desktop dev tool (Nexterm from scratch. Based in Hong Kong, fast turnaround. prajwalfullstack prajwalfullstack Hi Im a full stack developer, a vibe coded MVP to Market ready product, I'm here to help Yovel Cohen Yovel Cohen I got a lot of experience in building Long-horizon AI Agents in production, Backend apps that scale to millions of users and frontend knowledge as well. Krishna Sai Kuncha Krishna Sai Kuncha Experienced Professional Full stack Developer with 8+ years of experience across react, python, js, ts, golang and react-native. Developed inhouse websearch tooling for AI before websearch was solved : ) Nam Tran Nam Tran 10 years as fullstack developer Alvin Voo Alvin Voo I’ve watched the tech landscape evolve over the last decade—from the structured days of Java Server Pages to the current "wild west" of Agentic-driven development. While AI can "vibe" a frontend into existence, I specialize in the architecture that keeps it from collapsing. My expertise lies in the critical backend infrastructure: the parts that must be fast, secure, and scalable. I thrive on high-pressure environments, such as when I had only three weeks to architect and launch an Ethereum redemption system with minimal prior crypto knowledge, turning it into a major revenue stream. What I bring to your project: Forensic Debugging: I don't just "patch" bugs; I use tools like Datadog and Explain Analyzers to map out bottlenecks and resolve root causes—like significantly reducing memory usage by optimizing complex DB joins. Full-Stack Context: Deep experience in Node.js and React, ensuring backends play perfectly with mobile and web teams. Sanity in the Age of AI: I bridge the gap between "best practices" and modern speed, ensuring your project isn't just built fast, but built to last. Dor Yaloz Dor Yaloz SW engineer with 6+ years of experience, I worked with React/Node/Python did projects with React+Capacitor.js for ios Supabase expert BurnHavoc BurnHavoc Been around fixing other peoples code for 20 years. Victor Denisov Victor Denisov Developer Vlad Temian Vlad Temian 15+ years shipping production infrastructure for startups. Former CTO at qed.builders (acquired by The Sandbox). Cursor ambassador and agentic tooling builder. I've scaled systems, automated deployments, and built observability tools for AI coding workflows. I specialize in taking vibe-coded apps from broken prototype to production-ready: fixing Supabase auth/RLS, Stripe integrations, deployment pipelines, and cleaning up AI-generated spaghetti. I build tools in this space (agentprobe, claudebin, micode) and understand both sides: how AI generates code and why it breaks. https://blog.vtemian.com/

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Frequently 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.

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