Write-Ahead Logging (WAL) & ARIES Recovery
How do databases guarantee ACID Durability without grinding write throughput to a halt?
⚡ The WAL Protocol
Before any data page in shared buffers can be flushed to table storage, the corresponding log record must already exist on non-volatile disk.
🛠️ The ARIES Phase Trio
- Analysis Phase: Reconstructs dirty page tables from last checkpoint.
- Redo Phase: Repeats history to recover state at the moment of crash.
- Undo Phase: Rolls back operations of all uncommitted transactions.
Read the complete storage engine lesson on Binary Dose.
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