#MySQL Transactions and Locks

#Key Concepts

• Isolation levels: RU / RC / RR / SERIALIZABLE
• Lock types: row lock, gap lock and next-key lock
• Deadlocks are expected; fast detection and retry matter most

#Troubleshooting Path

1. Inspect deadlock reports in InnoDB status.
2. Review hot SQL and index hit ratio.
3. Reduce transaction scope and enforce access order.