asked known elsewhere

3 files changed, 23 insertions, 2 deletions

diff --git a/src/swarm/stats.rs b/src/swarm/stats.rs
index b51a802..191f4e9 100644
--- a/src/swarm/stats.rs
+++ b/src/swarm/stats.rs
@@ -146,6 +146,11 @@ pub(crate) struct Relay {
     /// The changes new to us that sync messages brought (beside what they carried that
     /// we had): with `carrying` less `nothing_new`, how many a message with news brings.
     pub(crate) new_changes: u64,
+    /// Changes peers asked for that we had counted as theirs, as another parent in
+    /// their writer's tree brings them (`SyncSession::known_to_peer`): within 2 s of
+    /// counting them so (so they weren't what we passed on built on), and later.
+    pub(crate) asked_known_lately: u64,
+    pub(crate) asked_known_later: u64,
     /// Changes from elsewhere that came not along a writer's tree (pulled, with an
     /// answer, sent again, fetched as a delta), and their delays summed (as `Propagation`).
     pub(crate) off_tree: u64,
@@ -285,6 +290,15 @@ impl NodeStats {
         inner.relay.carrying_bloom_bytes += sizes.1 as u64;
     }
 
+    /// A peer asked for changes we had counted as its (`SyncSession::resend_if_needed`).
+    pub(crate) fn asked_known_elsewhere(&self, (lately, later): (usize, usize)) {
+        if lately + later > 0 {
+            let mut inner = self.lock();
+            inner.relay.asked_known_lately += lately as u64;
+            inner.relay.asked_known_later += later as u64;
+        }
+    }
+
     /// A sync message brought `count` changes new to us.
     pub(crate) fn new_changes(&self, count: usize) {
         self.lock().relay.new_changes += count as u64;
diff --git a/src/swarm/sync.rs b/src/swarm/sync.rs
index c76c16b..6c67e57 100644
--- a/src/swarm/sync.rs
+++ b/src/swarm/sync.rs
@@ -497,7 +497,10 @@ pub(crate) async fn handle_sync(
             }
             peer_state.sync.reply_settled();
 
-            peer_state.sync.resend_if_needed(&replica.doc, &peer);
+            let asked = peer_state
+                .sync
+                .resend_if_needed(&replica.doc, &peer, Instant::now());
+            stats.asked_known_elsewhere(asked);
             replica.refresh_heads();
             let heads_after = replica.heads().to_vec();
             if delivered {
diff --git a/src/swarm/tree.rs b/src/swarm/tree.rs
index ffdf80e..d6d4a35 100644
--- a/src/swarm/tree.rs
+++ b/src/swarm/tree.rs
@@ -394,7 +394,11 @@ pub(crate) async fn forward(
             let mut peer_state = peer_state.lock().await;
             peer_state.tree_writer = Some(writer);
             if let Some(replica) = &replica {
-                peer_state.sync.with_predecessors(&replica.doc, changes);
+                peer_state.sync.with_predecessors(
+                    &replica.doc,
+                    changes,
+                    tokio::time::Instant::now(),
+                );
             }
         }
         state.stats.tree_forward();