prisma-risk / tsoracle / 26375487257

95%

Build Type

push

github

Committed by web-flow

Commit Message

fix(driver-paxos): seed the apply cursor from the recovery fold instead of re-draining from 0 (#330)

`StandaloneHost::new` already folds the recovered decided suffix to resume
the barrier-nonce counter, which yields the decided index recovery left off
at. But the spawned apply task initialized its decided-log cursor to 0 and
re-drained the entire decided log on its first wake. The fold is idempotent,
so this was correct — but it cost O(decided-log-length) redundant work at
startup on long-lived nodes.

The defect was a divergence between two independent cursor seeds: the
synchronous stepping path's cursor (seeded correctly from recovery) and the
async apply task's task-local cursor (hardcoded to 0). Collapse them into a
single shared `apply_cursor` seeded once in `new` from the recovery fold and
consumed by whichever drive path runs. A host is driven by exactly one path,
so the lock is uncontended; the seed can no longer disagree across paths, so
the re-drain cannot recur.

The parking_lot guard is dropped before the apply task's yield point (it is
!Send and may not cross the await). Behavior is unchanged for both paths
beyond skipping the redundant startup drain.

Closes #257

Coverage Stats

100 of 102 new or added lines in 2 files covered. (98.04%)

4 existing lines in 2 files now uncovered.

11519 of 12138 relevant lines covered (94.9%)

446788.11 hits per line