Write-Ahead Logging and Crash Recovery: Steal/No-Force Buffer Pools, ARIES (Analysis, Redo, Undo), Fuzzy Checkpoints, Torn Pages, and Group Commit

Deep End Era. Engineering with Sankalp · Oct 29, 2026 · 1h

When the breaker trips at two in the morning in the middle of a peak payment batch, your database has dirty uncommitted pages already written to solid-state storage and committed transactions still sitting exclusively in volatile RAM. Yet four seconds after power returns, every committed dirham is present and every half-finished transfer has vanished as if it never existed. To understand how that magic trick actually works on real hardware, we dissect Steal/No-Force buffer management, C. Mohan's ARIES recovery protocol, physiological logging, Compensation Log Records, fuzzy checkpoints…