Add in metrics for detecting Redundant Pulls (#199)

gossip/src/cluster_info_metrics.rs

@@ -315,6 +315,11 @@ pub(crate) fn submit_gossip_stats(
             stats.process_pull_response_timeout.clear(),
             i64
         ),
+        (
+            "num_redundant_pull_responses",
+            crds_stats.num_redundant_pull_responses,
+            i64
+        ),
         (
             "push_response_count",
             stats.push_response_count.clear(),

gossip/src/crds.rs

@@ -115,6 +115,9 @@ pub(crate) struct CrdsDataStats {
 pub(crate) struct CrdsStats {
     pub(crate) pull: CrdsDataStats,
     pub(crate) push: CrdsDataStats,
+    /// number of times a message was first received via a PullResponse
+    /// and that message was later received via a PushMessage
+    pub(crate) num_redundant_pull_responses: u64,
 }
 
 /// This structure stores some local metadata associated with the CrdsValue
@@ -127,8 +130,10 @@ pub struct VersionedCrdsValue {
     pub(crate) local_timestamp: u64,
     /// value hash
     pub(crate) value_hash: Hash,
-    /// Number of times duplicates of this value are recevied from gossip push.
-    num_push_dups: u8,
+    /// None -> value upserted by GossipRoute::{LocalMessage,PullRequest}
+    /// Some(0) -> value upserted by GossipRoute::PullResponse
+    /// Some(k) if k > 0 -> value upserted by GossipRoute::PushMessage w/ k - 1 push duplicates
+    num_push_recv: Option<u8>,
 }
 
 #[derive(Clone, Copy, Default)]
@@ -147,14 +152,21 @@ impl Cursor {
 }
 
 impl VersionedCrdsValue {
-    fn new(value: CrdsValue, cursor: Cursor, local_timestamp: u64) -> Self {
+    fn new(value: CrdsValue, cursor: Cursor, local_timestamp: u64, route: GossipRoute) -> Self {
         let value_hash = hash(&serialize(&value).unwrap());
+        let num_push_recv = match route {
+            GossipRoute::LocalMessage => None,
+            GossipRoute::PullRequest => None,
+            GossipRoute::PullResponse => Some(0),
+            GossipRoute::PushMessage(_) => Some(1),
+        };
+
         VersionedCrdsValue {
             ordinal: cursor.ordinal(),
             value,
             local_timestamp,
             value_hash,
-            num_push_dups: 0u8,
+            num_push_recv,
         }
     }
 }
@@ -222,7 +234,7 @@ impl Crds {
     ) -> Result<(), CrdsError> {
         let label = value.label();
         let pubkey = value.pubkey();
-        let value = VersionedCrdsValue::new(value, self.cursor, now);
+        let value = VersionedCrdsValue::new(value, self.cursor, now, route);
         match self.table.entry(label) {
             Entry::Vacant(entry) => {
                 self.stats.lock().unwrap().record_insert(&value, route);
@@ -303,8 +315,12 @@ impl Crds {
                     Err(CrdsError::InsertFailed)
                 } else if matches!(route, GossipRoute::PushMessage(_)) {
                     let entry = entry.get_mut();
-                    entry.num_push_dups = entry.num_push_dups.saturating_add(1);
-                    Err(CrdsError::DuplicatePush(entry.num_push_dups))
+                    if entry.num_push_recv == Some(0) {
+                        self.stats.lock().unwrap().num_redundant_pull_responses += 1;
+                    }
+                    let num_push_dups = entry.num_push_recv.unwrap_or_default();
+                    entry.num_push_recv = Some(num_push_dups.saturating_add(1));
+                    Err(CrdsError::DuplicatePush(num_push_dups))
                 } else {
                     Err(CrdsError::InsertFailed)
                 }
@@ -1450,8 +1466,9 @@ mod tests {
     #[allow(clippy::neg_cmp_op_on_partial_ord)]
     fn test_equal() {
         let val = CrdsValue::new_unsigned(CrdsData::LegacyContactInfo(ContactInfo::default()));
-        let v1 = VersionedCrdsValue::new(val.clone(), Cursor::default(), 1);
-        let v2 = VersionedCrdsValue::new(val, Cursor::default(), 1);
+        let v1 =
+            VersionedCrdsValue::new(val.clone(), Cursor::default(), 1, GossipRoute::LocalMessage);
+        let v2 = VersionedCrdsValue::new(val, Cursor::default(), 1, GossipRoute::LocalMessage);
         assert_eq!(v1, v2);
         assert!(!(v1 != v2));
         assert!(!overrides(&v1.value, &v2));
@@ -1467,6 +1484,7 @@ mod tests {
             ))),
             Cursor::default(),
             1, // local_timestamp
+            GossipRoute::LocalMessage,
         );
         let v2 = VersionedCrdsValue::new(
             {
@@ -1476,6 +1494,7 @@ mod tests {
             },
             Cursor::default(),
             1, // local_timestamp
+            GossipRoute::LocalMessage,
         );
 
         assert_eq!(v1.value.label(), v2.value.label());
@@ -1501,6 +1520,7 @@ mod tests {
             ))),
             Cursor::default(),
             1, // local_timestamp
+            GossipRoute::LocalMessage,
         );
         let v2 = VersionedCrdsValue::new(
             CrdsValue::new_unsigned(CrdsData::LegacyContactInfo(ContactInfo::new_localhost(
@@ -1509,6 +1529,7 @@ mod tests {
             ))),
             Cursor::default(),
             1, // local_timestamp
+            GossipRoute::LocalMessage,
         );
         assert_eq!(v1.value.label(), v2.value.label());
         assert!(overrides(&v1.value, &v2));
@@ -1527,6 +1548,7 @@ mod tests {
             ))),
             Cursor::default(),
             1, // local_timestamp
+            GossipRoute::LocalMessage,
         );
         let v2 = VersionedCrdsValue::new(
             CrdsValue::new_unsigned(CrdsData::LegacyContactInfo(ContactInfo::new_localhost(
@@ -1535,6 +1557,7 @@ mod tests {
             ))),
             Cursor::default(),
             1, // local_timestamp
+            GossipRoute::LocalMessage,
         );
         assert_ne!(v1, v2);
         assert!(!(v1 == v2));