| name | 0.2.3-understand-tl_update_record |
| description | [0.2.3] A log_record capturing a before_image and after_image of a modified data page or row; used by both redo_recove |
understand-tl_update_record
CALL NUMBER: deep_database_transaction.tl_update_record
DEFINITION: A log_record capturing a before_image and after_image of a modified data page or row; used by both redo_recovery (for durability) and undo_recovery (for atomicity rollback).
Invoke this skill to understand tl_update_record 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_redo_log (d1): A log_record or series of tl_update_record entries capturing the after_image of modifications; replayed by recovery_manager to idempotently reconstruct committed changes after a crash.
- tl_undo_log (d1): 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.
- tl_abort_record (d2): 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_log_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.)
