Inherit transaction count from parent (#3134)

runtime/src/accounts.rs

@@ -220,6 +220,7 @@ impl AccountsDB {
         if let Some(parent) = parent {
             fork_info.parents.push(parent);
             if let Some(parent_fork_info) = fork_infos.get(&parent) {
+                fork_info.transaction_count = parent_fork_info.transaction_count;
                 fork_info
                     .parents
                     .extend_from_slice(&parent_fork_info.parents);
@@ -720,10 +721,6 @@ impl AccountsDB {
     /// make fork a root, i.e. forget its heritage
     fn squash(&self, fork: Fork) {
         let parents = self.remove_parents(fork);
-        let tx_count = parents
-            .iter()
-            .fold(0, |sum, parent| sum + self.transaction_count(*parent));
-        self.increment_transaction_count(fork, tx_count as usize);
 
         // for every account in all the parents, load latest and update self if
         // absent
@@ -1783,4 +1780,24 @@ mod tests {
         );
         assert_eq!(error_counters.account_not_found, 1);
     }
+
+    #[test]
+    fn test_accountsdb_inherit_tx_count() {
+        let paths = get_tmp_accounts_path!();
+        let accounts = AccountsDB::new(0, &paths.paths);
+        cleanup_paths(&paths.paths);
+        assert_eq!(accounts.transaction_count(0), 0);
+        accounts.increment_transaction_count(0, 1);
+        assert_eq!(accounts.transaction_count(0), 1);
+        // fork and check that tx count is inherited
+        accounts.add_fork(1, Some(0));
+        assert_eq!(accounts.transaction_count(1), 1);
+        // Parent fork shouldn't change
+        accounts.increment_transaction_count(1, 1);
+        assert_eq!(accounts.transaction_count(1), 2);
+        assert_eq!(accounts.transaction_count(0), 1);
+        // Squash shouldn't effect tx count
+        accounts.squash(1);
+        assert_eq!(accounts.transaction_count(1), 2);
+    }
 }

runtime/src/bank.rs

@@ -1417,11 +1417,12 @@ mod tests {
         assert_eq!(parent.transaction_count(), 1);
 
         let bank = new_from_parent(&parent);
-        assert_eq!(bank.transaction_count(), 0);
+        assert_eq!(bank.transaction_count(), parent.transaction_count());
         let tx_move_1_to_2 =
             SystemTransaction::new_move(&key1, key2.pubkey(), 1, genesis_block.hash(), 0);
         assert_eq!(bank.process_transaction(&tx_move_1_to_2), Ok(()));
-        assert_eq!(bank.transaction_count(), 1);
+        assert_eq!(bank.transaction_count(), 2);
+        assert_eq!(parent.transaction_count(), 1);
         assert_eq!(
             parent.get_signature_status(&tx_move_1_to_2.signatures[0]),
             None