skills:interview
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| 18. What are deadlocks? | 18. What are deadlocks? | ||
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| + | - Deadlock: A situation where two or more transactions hold locks and wait for each other indefinitely. | ||
| + | - How it occurs: Transactions access the same resources in different orders. Long-running transactions hold locks too long. Missing indexes cause unnecessary locking. | ||
| + | - How to detect it: The database detects deadlocks automatically. MySQL returns: ERROR 1213: Deadlock found when trying to get lock. Investigate with SHOW ENGINE INNODB STATUS. | ||
| + | - How to prevent it: Keep transactions short. Always access tables/rows in a consistent order. Add proper indexes. Avoid large batch operations in a single transaction. | ||
| + | - How to recover: The database rolls back one transaction automatically. Catch the error in the application and retry the transaction with backoff. | ||
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| ==== Large Scale Databases ==== | ==== Large Scale Databases ==== | ||
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| - | ====== System Design Interview Questions | + | ====== System Design Interview Questions ====== |
| ===== Interview Framework ===== | ===== Interview Framework ===== | ||
skills/interview.1781517788.txt.gz · Last modified: by phong2018