What is ACID
ACID is an acronym for Atomicity, Consistency, Isolation, and Durability. These four properties ensure that every database transaction happens in a reliable way, even if errors or system failures happen. They`re at the heart of data integrity in relational databases.
How It Works
When a transaction starts, every operation follows the ACID rules. If something fails, the database undoes any partial changes to avoid corrupt data. If everything is successful, all the changes are saved. This approach prevents data from getting messed up.
Technical Details
Behind the scenes, database engines use logs, locks, and close coordination to enforce ACID. They keep track of each step to make sure every change either happens completely or not at all. They also isolate concurrent transactions from each other and guarantee that changes aren`t lost once committed.
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Best Practices
- Wrap multiple statements in a transaction to keep data consistent
- Avoid long-running transactions that block other operations
- Use logs to record errors that cause rollbacks
- Keep regular backups for extra safety
Common Pitfalls
- Skipping transactions when updating more than one table at a time
- Relying on auto-commit without a clear grasp of ACID guarantees
- Overlooking concurrency problems or ignoring isolation levels
- Not planning for data recovery in serious failures
Advanced Tips
- Pick the right isolation level based on how much concurrency you need
- Use savepoints for complex transactions that might fail in parts
- Consider distributed transactions in multi-node setups for extra reliability
- Tweak database settings to optimize transaction lock performance
