Skip to content

test(cache): sample metrics before final read in refresh_dropped_when_hard_miss_races #881

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
Dodothereal wants to merge 1 commit into
base: main
Choose a base branch
from
+12 −9
Draft

test(cache): sample metrics before final read in refresh_dropped_when_hard_miss_races #881

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
21 changes: 12 additions & 9 deletions crates/cache/src/tests.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -619,15 +619,9 @@ async fn refresh_dropped_when_hard_miss_races() {
// discarded by the identity guard, NOT inserted on top of n=3.
tokio::time::sleep(Duration::from_millis(150)).await;

// 6. Subsequent reads still see n=3. The post-hard-miss entry is ~150ms
// old now (well within the 200ms hard TTL). If the refresh had clobbered,
// we'd see n=2 here.
let v4 = cache.get("k".into()).await.unwrap().unwrap();
assert_eq!(
v4, "n=3",
"stale refresh must not overwrite the post-hard-miss value"
);

// 6. Check metrics immediately after the slow refresh finishes, before any
// subsequent read. The slow refresh (n=2) must have been dropped by the
// identity guard, not written back.
let m = cache.metrics().snapshot();
assert_eq!(
m.refresh_success, 0,
Expand All @@ -637,6 +631,15 @@ async fn refresh_dropped_when_hard_miss_races() {
m.refresh_dropped_epoch >= 1,
"the slow refresh must be counted as dropped; got {m:?}"
);

// 7. Subsequent reads still see n=3. The post-hard-miss entry is ~150ms
// old now (well within the 200ms hard TTL). If the refresh had clobbered,
// we'd see n=2 here.
let v4 = cache.get("k".into()).await.unwrap().unwrap();
assert_eq!(
v4, "n=3",
"stale refresh must not overwrite the post-hard-miss value"
);
}

/// PR1 H4: a panicking loader must NOT leak `refresh_in_flight = true`.
Expand Down