Safe Commits

Honest by Construction

Expected facts are assertions only; compiler output is the source of truth.

highlighted = computed this step

Honest by construction

The book compiles raw schedules, turns recomputed facts into expected assertions, then compiles again before rendering.

expected is assertion only\text{expected is assertion only}

Show the guarded example

The guarded schedule has 1 reads-from fact and 2 classification violations.

reads-from=1\text{reads-from}=1

Safe commit and rollback schedules are tiny finite histories; logging, undo, ARIES, timing, isolation-level, product, and performance claims are out of scope.

Guarded recoverability factseventtxopitemvalue1T1wX102T2rX3T1c4T2c reads-from factsreadEventreaderitemwriterwriteEventvalue2T2XT1110 external read dependencieswriterreaderitemwriteEventreadEventT1T2X12 classificationsfactvaluerecoverableyescascadelessnostrictno violationsnkindtx/readerwriteritem1cascadelessT2T1X2strictT2T1X

Try to tamper

Wrong expected facts, derived sidecars, and reads with no modeled source fail closed before any lesson artifact can be trusted.

fail closed before render\text{fail closed before render}

Summary

The book stays inside exact schedule classification; recovery mechanisms and database products are out of scope.

recomputed schedule facts\text{recomputed schedule facts}