Don't add transactions to a pool in non-validator nodes

chain/chunks/src/lib.rs

@@ -492,6 +492,7 @@ impl ShardsManager {
         network_adapter: Arc<dyn PeerManagerAdapter>,
         rng_seed: RngSeed,
     ) -> Self {
+        TransactionPool::init_metrics();
         Self {
             me: me.clone(),
             tx_pools: HashMap::new(),

chain/pool/src/lib.rs

@@ -17,9 +17,9 @@ pub struct TransactionPool {
     /// Transactions are grouped by a pair of (account ID, signer public key).
     /// NOTE: It's more efficient on average to keep transactions unsorted and with potentially
     /// conflicting nonce than to create a BTreeMap for every transaction.
-    pub transactions: BTreeMap<PoolKey, Vec<SignedTransaction>>,
+    transactions: BTreeMap<PoolKey, Vec<SignedTransaction>>,
     /// Set of all hashes to quickly check if the given transaction is in the pool.
-    pub unique_transactions: HashSet<CryptoHash>,
+    unique_transactions: HashSet<CryptoHash>,
     /// A uniquely generated key seed to randomize PoolKey order.
     key_seed: RngSeed,
     /// The key after which the pool iterator starts. Doesn't have to be present in the pool.
@@ -36,6 +36,11 @@ impl TransactionPool {
         }
     }
 
+    pub fn init_metrics() {
+        // A `get()` call initializes a metric even if its value is zero.
+        metrics::TRANSACTION_POOL_TOTAL.get();
+    }
+
     fn key(&self, account_id: &AccountId, public_key: &PublicKey) -> PoolKey {
         let mut v = public_key.try_to_vec().unwrap();
         v.extend_from_slice(&self.key_seed);
@@ -108,10 +113,6 @@ impl TransactionPool {
     pub fn len(&self) -> usize {
         self.unique_transactions.len()
     }
-
-    pub fn is_empty(&self) -> bool {
-        self.unique_transactions.is_empty()
-    }
 }
 
 /// PoolIterator is a structure to pull transactions from the pool.