0-2-4-understand-tl-undo-log

name	0.2.4-understand-tl_undo_log
description	[0.2.4] A structured collection of tl_update_record entries chained by a transaction; traversed in reverse order durin

understand-tl_undo_log

CALL NUMBER: deep_database_transaction.tl_undo_log DEFINITION: A structured collection of tl_update_record entries chained by a transaction; traversed in reverse order during rollback to restore the before_image of each modified entity.

Invoke this skill to understand tl_undo_log down to its primitives. The RELATIVE ROOT below is the least-fixed-point closure of everything it bundles from — the full import cone, grouped by the lib each prim comes from. Projected from a prover-typed KB (MAP/SWI-Prolog consistency gate): every reference below resolves.

THE RELATIVE ROOT (the import cone, by lib)

from deep_database_transaction

• tl_abort_record (d1): A log_record written when a transaction enters the aborted_state; signals that undo_log entries must be applied to reverse this transaction's effects.

CONSUMERS (what needs this)

tl_recovery_manager, tl_update_record

---

Projected from the database transaction isolation and concurrency control KB (217 concepts / 124 relations) — consistency-typed by MAP; the facet list after the colon IS the cross-lib dependency web.

(leaf — this is an actual skill.)