ben zhang e05028e7b0 Prefetch sibling rollout paths when reading history pages (#55396) ...

## Why

Resolving a history page's rollout lineage performs a separate filesystem lookup for each ancestor. Ancestors stored alongside the current rollout can share a lookup traversal.

## What changed

- Prefetch paths for up to 64 sibling rollout IDs belonging to the same thread when listing history turns or items.
- Resolve candidates in the normal lookup order to preserve first-match selection for duplicate rollout IDs.
- Validate prefetched paths before use and fall back to normal lookup for missing or stale paths. Treat prefetch failures as optional and continue with normal resolution.

## Testing

Add a regression test verifying that sibling prefetch selects the same first match for a duplicate rollout ID as normal lookup.

GitOrigin-RevId: 5d86c9643562a82a53af78b20f70322c1506c6e1

2026-10-19 22:04:38 +00:00

..

src

Prefetch sibling rollout paths when reading history pages (#55396)

2026-10-19 22:04:38 +00:00

BUILD.bazel

Extract rollout into its own crate (#15548)

2026-03-24 18:10:53 -07:00

Cargo.toml

Preserve rollout access metadata across compression and restoration (#55252)

2026-10-19 11:02:40 +00:00