metric: add unref_zero_count stat (#2791)

* add unref_zero_count stat * put unref_zero_count stat on accounts_index --------- Co-authored-by: HaoranYi <[email protected]>
anza-xyz · Aug 30, 2024 · 8a219de · 8a219de
1 parent f79cea1
commit 8a219de
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diff --git a/accounts-db/src/accounts_db.rs b/accounts-db/src/accounts_db.rs
@@ -3717,6 +3717,13 @@ impl AccountsDb {
                     .swap(0, Ordering::Relaxed),
                 i64
             ),
+            (
+                "unref_zero_count",
+                self.accounts_index
+                    .unref_zero_count
+                    .swap(0, Ordering::Relaxed),
+                i64
+            ),
             (
                 "ancient_account_cleans",
                 ancient_account_cleans.load(Ordering::Relaxed),

diff --git a/accounts-db/src/accounts_index.rs b/accounts-db/src/accounts_index.rs
@@ -687,6 +687,8 @@ pub struct AccountsIndex<T: IndexValue, U: DiskIndexValue + From<T> + Into<T>> {
     pub active_scans: AtomicUsize,
     /// # of slots between latest max and latest scan
     pub max_distance_to_min_scan_slot: AtomicU64,
+    // # of unref when the account's ref_count is zero
+    pub unref_zero_count: AtomicU64,
 
     /// populated at generate_index time - accounts that could possibly be rent paying
     pub rent_paying_accounts_by_partition: OnceLock<RentPayingAccountsByPartition>,
@@ -724,6 +726,7 @@ impl<T: IndexValue, U: DiskIndexValue + From<T> + Into<T>> AccountsIndex<T, U> {
             roots_removed: AtomicUsize::default(),
             active_scans: AtomicUsize::default(),
             max_distance_to_min_scan_slot: AtomicU64::default(),
+            unref_zero_count: AtomicU64::default(),
             rent_paying_accounts_by_partition: OnceLock::default(),
         }
     }
@@ -1452,6 +1455,7 @@ impl<T: IndexValue, U: DiskIndexValue + From<T> + Into<T>> AccountsIndex<T, U> {
                             AccountsIndexScanResult::Unref => {
                                 if locked_entry.unref() {
                                     info!("scan: refcount of item already at 0: {pubkey}");
+                                    self.unref_zero_count.fetch_add(1, Ordering::Relaxed);
                                 }
                                 true
                             }