Module object_version_by_checkpoint 

Sequential pipeline that populates the schema::object_version_by_checkpoint CF, which resolves an object’s version as of a checkpoint.

It writes three kinds of rows:

• Change rows (id, c) -> final version – one per object that changed in checkpoint c, carrying its final version at the end of c (a live version, or the tombstone version for an object deleted or wrapped and not re-created). Only the final version is recorded; intra-checkpoint intermediate versions stay addressable through the version-keyed objects CF.
• Restore floor rows (id, T) -> version, marked from_restore – one per live object at the restore anchor T, bulk-loaded by the restore impl. A read below T for an object that never changed in the available window falls back to these.
• Synthetic floor rows (id, 0) -> window-entry version – for an object that existed before the available window [L, T] and first changes within it, this records the version it entered the window with, so a read in [L, first-change) resolves to that instead of the newer restore floor. Written during the embedded backfill only: past T the restore floor already covers pre-window objects, so the dedup read is skipped. The row is keyed at checkpoint 0 (below the window, where L > 0) so the floor scan finds it, and the effects-driven pruner retracts it once the object’s first in-window change ages out.

Structs

ObjectVersionByCheckpoint

Pipeline marker for object_version_by_checkpoint.

Enums

Row

One staged write produced by process.