feat(op, txpool, metrics): add metric for removed conditional txs (#14541)

Cargo.lock

@@ -8744,11 +8744,13 @@ dependencies = [
  "c-kzg",
  "derive_more",
  "futures-util",
+ "metrics",
  "op-alloy-consensus",
  "op-alloy-flz",
  "parking_lot",
  "reth-chain-state",
  "reth-chainspec",
+ "reth-metrics",
  "reth-optimism-chainspec",
  "reth-optimism-evm",
  "reth-optimism-forks",

crates/optimism/txpool/Cargo.toml

@@ -35,6 +35,10 @@ reth-optimism-evm.workspace = true
 reth-optimism-forks.workspace = true
 reth-optimism-primitives = { workspace = true, features = ["reth-codec"] }
 
+# metrics
+reth-metrics.workspace = true
+metrics.workspace = true
+
 # misc
 c-kzg.workspace = true
 derive_more.workspace = true

crates/optimism/txpool/src/maintain.rs

@@ -1,12 +1,28 @@
 //! Support for maintaining the state of the transaction pool
 
+use crate::conditional::MaybeConditionalTransaction;
 use alloy_consensus::{conditional::BlockConditionalAttributes, BlockHeader};
 use futures_util::{future::BoxFuture, FutureExt, Stream, StreamExt};
 use reth_chain_state::CanonStateNotification;
+use reth_metrics::{metrics::Counter, Metrics};
 use reth_primitives_traits::NodePrimitives;
 use reth_transaction_pool::TransactionPool;
 
-use crate::conditional::MaybeConditionalTransaction;
+/// Transaction pool maintenance metrics
+#[derive(Metrics)]
+#[metrics(scope = "transaction_pool")]
+struct MaintainPoolMetrics {
+    /// Counter indicating the number of conditional transactions removed from
+    /// the pool because of exceeded block attributes.
+    removed_tx_conditional: Counter,
+}
+
+impl MaintainPoolMetrics {
+    #[inline]
+    fn inc_removed_tx_conditional(&self, count: usize) {
+        self.removed_tx_conditional.increment(count as u64);
+    }
+}
 
 /// Returns a spawnable future for maintaining the state of the transaction pool.
 pub fn maintain_transaction_pool_future<N, Pool, St>(
@@ -35,6 +51,7 @@ where
     Pool::Transaction: MaybeConditionalTransaction,
     St: Stream<Item = CanonStateNotification<N>> + Send + Unpin + 'static,
 {
+    let metrics = MaintainPoolMetrics::default();
     loop {
         let Some(event) = events.next().await else { break };
         if let CanonStateNotification::Commit { new } = event {
@@ -51,7 +68,10 @@ where
                     to_remove.push(*tx.hash());
                 }
             }
-            let _ = pool.remove_transactions(to_remove);
+            if !to_remove.is_empty() {
+                metrics.inc_removed_tx_conditional(to_remove.len());
+                let _ = pool.remove_transactions(to_remove);
+            }
         }
     }
 }