feat(txpool): add sub-pools length and size metrics

crates/transaction-pool/src/metrics.rs

@@ -1,6 +1,6 @@
 //! Transaction pool metrics.
 
-use metrics::Counter;
+use metrics::{Counter, Gauge};
 use reth_metrics_derive::Metrics;
 
 /// Transaction pool metrics
@@ -13,4 +13,23 @@ pub struct TxPoolMetrics {
     pub(crate) invalid_transactions: Counter,
     /// Number of removed transactions from the pool
     pub(crate) removed_transactions: Counter,
+    /// Total number of transactions in the pool
+    pub(crate) total_number_transactions: Gauge,
+    /// Total amount of memory used by the transactions in the pool in bytes
+    pub(crate) total_size_bytes: Gauge,
+
+    /// Number of transactions in the pending sub-pool
+    pub(crate) pending_pool_length: Gauge,
+    /// Total amount of memory used by the transactions in the pending sub-pool in bytes
+    pub(crate) pending_sub_pool_size_bytes: Gauge,
+
+    /// Number of transactions in the basefee sub-pool
+    pub(crate) basefee_pool_length: Gauge,
+    /// Total amount of memory used by the transactions in the basefee sub-pool in bytes
+    pub(crate) basefee_sub_pool_size_bytes: Gauge,
+
+    /// Number of transactions in the queued sub-pool
+    pub(crate) queued_pool_length: Gauge,
+    /// Total amount of memory used by the transactions in the queued sub-pool in bytes
+    pub(crate) queued_sub_pool_size_bytes: Gauge,
 }

crates/transaction-pool/src/pool/txpool.rs

@@ -110,6 +110,10 @@ impl<T: TransactionOrdering> TxPool<T> {
     /// Returns stats about the size of pool.
     pub(crate) fn size(&self) -> PoolSize {
         PoolSize {
+            total_transactions: self.len(),
+            total_size: self.pending_pool.size() +
+                self.basefee_pool.size() +
+                self.queued_pool.size(),
             pending: self.pending_pool.len(),
             pending_size: self.pending_pool.size(),
             basefee: self.basefee_pool.len(),
@@ -253,6 +257,17 @@ impl<T: TransactionOrdering> TxPool<T> {
         // Process the sub-pool updates
         let UpdateOutcome { promoted, discarded } = self.process_updates(updates);
 
+        // Compute pool metrics
+        let stats = self.size();
+        self.metrics.total_number_transactions.set(stats.total_transactions as f64);
+        self.metrics.total_size_bytes.set(stats.total_size as f64);
+        self.metrics.pending_pool_length.set(stats.pending as f64);
+        self.metrics.pending_sub_pool_size_bytes.set(stats.pending_size as f64);
+        self.metrics.basefee_pool_length.set(stats.basefee as f64);
+        self.metrics.basefee_sub_pool_size_bytes.set(stats.basefee_size as f64);
+        self.metrics.queued_pool_length.set(stats.queued as f64);
+        self.metrics.queued_sub_pool_size_bytes.set(stats.queued_size as f64);
+
         OnNewCanonicalStateOutcome { block_hash, mined: mined_transactions, promoted, discarded }
     }
 

crates/transaction-pool/src/traits.rs

@@ -557,6 +557,10 @@ impl IntoRecoveredTransaction for PooledTransaction {
 /// Represents the current status of the pool.
 #[derive(Debug, Clone)]
 pub struct PoolSize {
+    /// Number of transactions in the pool.
+    pub total_transactions: usize,
+    /// Reported size of transactions in the pool.
+    pub total_size: usize,
     /// Number of transactions in the _pending_ sub-pool.
     pub pending: usize,
     /// Reported size of transactions in the _pending_ sub-pool.

docs/design/metrics.md

@@ -77,6 +77,14 @@ This list may be non-exhaustive.
 - `transaction_pool.inserted_transactions`: Number of transactions inserted in the pool
 - `transaction_pool.invalid_transactions`: Number of invalid transactions 
 - `transaction_pool.removed_transactions`: Number of removed transactions from the pool
+- `transaction_pool.total_number_transactions`: Total number of transactions in the pool
+- `transaction_pool.total_size_bytes`: Total amount of memory used by the transactions in the pool in bytes
+- `transaction_pool.pending_sub_pool_length`: Number of transactions in the pending sub-pool
+- `transaction_pool.pending_sub_pool_size_bytes`: Total amount of memory used by the transactions in the pending sub-pool in bytes
+- `transaction_pool.basefee_sub_pool_length`: Number of transactions in the basefee sub-pool
+- `transaction_pool.basefee_sub_pool_size_bytes`: Total amount of memory used by the transactions in the basefee sub-pool in bytes
+- `transaction_pool.queued_sub_pool_length`: Number of transactions in the queued sub-pool
+- `transaction_pool.queued_sub_pool_size_bytes`: Total amount of memory used by the transactions in the queued sub-pool in bytes
 
 #### Component: Network