Module object_version_by_checkpoint 

(ObjectID, checkpoint) -> version.

Resolves an object’s version as of a checkpoint: the version it had at the end of the most recent checkpoint, at or before the one queried, in which it changed. One row is written per (object, checkpoint-it-changed-in), carrying the object’s final version in that checkpoint – a live version, or the tombstone version at which it was deleted or wrapped.

The key is the 32-byte object id followed by an 8-byte big-endian checkpoint, so a reverse prefix scan from (id, C) lands on the greatest checkpoint <= C – the object’s state as of C. This is the checkpoint-pinned counterpart to the version-keyed super::objects CF (which answers “object at version V” but not “object as of checkpoint C”), and the analog of the indexer’s Postgres obj_versions table that the GraphQL service relies on for checkpoint_viewed_at historical reads.

Rows carry a from_restore provenance flag, set only by the live-set restore at the anchor checkpoint and left unset by tip indexing and backfill. It lets a read whose checkpoint falls before any recorded change fall back to the restore floor – telling an object that existed before the available window (and so is live at the queried checkpoint) apart from one created later. See get_object_version_at_checkpoint.

Pruning is effects-driven, in lockstep with super::objects: a transaction that supersedes an object retracts that object’s checkpoint-pinned entries below the superseding checkpoint, so the retained set always matches the versions super::objects keeps (the floor at the retention boundary, and everything newer).

Structs

Key

(ObjectID, checkpoint). Encoded as 32 raw id bytes followed by an 8-byte big-endian checkpoint sequence number, so the rows for one object cluster together in ascending checkpoint order and a reverse scan resolves the floor checkpoint for a point-in-time read.

ObjectIdPrefix

Prefix encoder for “every checkpoint at which id changed”. Encodes as the 32 raw id bytes – the leading bytes of every Key whose id matches.

Constants

NAME

Functions

options

store

Build the (Key, Value) pair recording that, as of checkpoint, the object id’s final version was version. Written by tip indexing and backfill; from_restore is left unset so these (the common case) pay no extra bytes.

store_restored

Like store, but marks the row as written by the live-set restore at the anchor checkpoint (from_restore = Some(true)). The checkpoint-pinned read uses this flag to tell a static object’s restore floor (the object existed before the available window) apart from an object created in the anchor checkpoint.

Type Aliases

Value

The object’s final version in the keyed checkpoint, plus a from_restore provenance flag (set only on rows written by the live-set restore at the anchor checkpoint).