{"id":"wal-durability-effective-on-standards-compliant-fsync","text":"The WAL's two-tier durability model provides effective crash protection: critical operations (checkpoints, batch commits, rotations) unconditionally force fsync while per-write sync respects the configured mode, creating a meaningful durability hierarchy where batch boundaries are always durable regardless of the performance/durability tradeoff chosen for individual writes.","truth_value":"OUT","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["wal-two-tier-durability-model","critical-wal-operations-always-force-fsync"],"outlist":["macos-fsync-not-durable-without-fullfsync"],"label":"Two depth-1 conclusions about WAL durability form a coherent positive model, gated on the macOS fsync limitation — on Darwin, os.fsync() may not flush the disk write cache, undermining the entire durability hierarchy on the development platform"}],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"wal-durability-effective-on-standards-compliant-fsync","truth_value":"OUT","reason":"SL justification invalid","failed_antecedents":[],"label":"Two depth-1 conclusions about WAL durability form a coherent positive model, gated on the macOS fsync limitation — on Darwin, os.fsync() may not flush the disk write cache, undermining the entire durability hierarchy on the development platform","violated_outlist":["macos-fsync-not-durable-without-fullfsync"]}]}}