Compute serialized size on the fly

zebrad/src/components/mempool/storage/verified_set.rs

@@ -26,10 +26,6 @@ pub struct VerifiedSet {
     /// The set of verified transactions in the mempool.
     transactions: VecDeque<UnminedTx>,
 
-    /// The total size of the transactions in the mempool if they were
-    /// serialized.
-    transactions_serialized_size: usize,
-
     /// The set of spent out points by the verified transactions.
     spent_outpoints: HashSet<transparent::OutPoint>,
 
@@ -54,6 +50,11 @@ impl VerifiedSet {
         self.transactions.len()
     }
 
+    /// Returns the total serialized size of the transactions in the set.
+    pub fn transactions_serialized_size(&self) -> usize {
+        self.transactions().map(|tx| tx.size).sum()
+    }
+
     /// Returns `true` if the set of verified transactions contains the transaction with the
     /// specified `id.
     pub fn contains(&self, id: &UnminedTxId) -> bool {
@@ -69,7 +70,6 @@ impl VerifiedSet {
         self.sprout_nullifiers.clear();
         self.sapling_nullifiers.clear();
         self.orchard_nullifiers.clear();
-        self.transactions_serialized_size = 0;
         self.update_metrics();
     }
 
@@ -86,7 +86,6 @@ impl VerifiedSet {
         }
 
         self.cache_outputs_from(&transaction.transaction);
-        self.transactions_serialized_size += transaction.size;
         self.transactions.push_front(transaction);
 
         self.update_metrics();
@@ -143,7 +142,6 @@ impl VerifiedSet {
             .remove(transaction_index)
             .expect("invalid transaction index");
 
-        self.transactions_serialized_size -= removed_tx.size;
         self.remove_outputs(&removed_tx);
 
         self.update_metrics();
@@ -216,7 +214,7 @@ impl VerifiedSet {
         );
         metrics::gauge!(
             "zcash.mempool.size.bytes",
-            self.transactions_serialized_size as _
+            self.transactions_serialized_size() as _
         );
     }
 }